WO2024194789A1 - System and method for determining arousals and arousal-associated events of a sleep study using non-brain body signals or without requiring brain signals - Google Patents
System and method for determining arousals and arousal-associated events of a sleep study using non-brain body signals or without requiring brain signals Download PDFInfo
- Publication number
- WO2024194789A1 WO2024194789A1 PCT/IB2024/052615 IB2024052615W WO2024194789A1 WO 2024194789 A1 WO2024194789 A1 WO 2024194789A1 IB 2024052615 W IB2024052615 W IB 2024052615W WO 2024194789 A1 WO2024194789 A1 WO 2024194789A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- sleep
- signals
- arousal
- respiratory
- ahi
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/48—Other medical applications
- A61B5/4806—Sleep evaluation
- A61B5/4818—Sleep apnoea
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/08—Measuring devices for evaluating the respiratory organs
- A61B5/0826—Detecting or evaluating apnoea events
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/08—Measuring devices for evaluating the respiratory organs
- A61B5/085—Measuring impedance of respiratory organs or lung elasticity
- A61B5/086—Measuring impedance of respiratory organs or lung elasticity by impedance pneumography
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Measuring devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb
- A61B5/113—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb occurring during breathing
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/103—Measuring devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
- A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb
- A61B5/113—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb occurring during breathing
- A61B5/1135—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb occurring during breathing by monitoring thoracic expansion
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/316—Modalities, i.e. specific diagnostic methods
- A61B5/369—Electroencephalography [EEG]
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/48—Other medical applications
- A61B5/4806—Sleep evaluation
- A61B5/4809—Sleep detection, i.e. determining whether a subject is asleep or not
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
- A61B5/6813—Specially adapted to be attached to a specific body part
- A61B5/6823—Trunk, e.g., chest, back, abdomen, hip
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
- A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
- A61B5/683—Means for maintaining contact with the body
- A61B5/6831—Straps, bands or harnesses
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7235—Details of waveform analysis
- A61B5/7264—Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7235—Details of waveform analysis
- A61B5/7264—Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems
- A61B5/7267—Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems involving training the classification device
Definitions
- the present disclosure relates to a system, apparatuses, and a method for determining arousals and sleep stages of a subject, and particularly for determining arousals and sleep stages based on signals obtained from the body of the subject without necessarily being signals obtained from the brain or heart of the subject.
- BACKGROUND [0006] Clinical sleep studies of different types have been developed. Such studies have either focused on measuring or identifying a specific sleep disorder or have been more general for measuring the overall sleep profile along with the signals necessary to confirm or exclude different sleep disorders.
- Polysomnography (PSG) is a general sleep study that records various physiological signals.
- a PSG is generally considered a complicated study and usually requires professional assistance by certified or credential technologists to setup, perform, and monitor the PSG.
- PSG includes simultaneous recording of multiple signals, such as Electroencephalography (EEG), Electrooculography (EOG), Electromyography (EMG), Electrocardiography (ECG), Respiratory Flow, Respiratory Effort, Oximetry, Body Position, and/or more to achieve the required accuracy.
- EEG Electroencephalography
- EEG Electrooculography
- EMG Electromyography
- ECG Electrocardiography
- Respiratory Flow Respiratory Effort
- Oximetry Oximetry
- Body Position and/or more to achieve the required accuracy.
- Standard PSG allows further classification of the NREM periods on different levels of sleep including N1, N2, and N3, with N1 being the shallowest, then N2, and finally N3.
- the N3 period is often referred to as deep sleep or Slow Wave Sleep due to the slow EEG signals that are characteristic of this period.
- the sleep stages are often presented in a graph with the X axis labeled with the time of day and the Y axis showing 5 values, Wake, REM, N1, N2, N3. A line may then be plotted showing the sleep stage of the subject at different times of the night or sleep study period. Such a graph is called hypnogram and is the standard presentation of the sleep profile used in PSG studies.
- the sleep indexes which are derived directly from the sleep study signals, often include an expansive collection of indices derived from the sleep study. These indices may include, but are not limited to: • Arousal Index: The number of arousals per hour of sleep. • Apnea-Hypopnea Index: The number of complete breathing cessations (apneas), and severely restricted breathing (hypopnea) events per hour of sleep. • Oxygen Desaturation Index: The number of blood oxygen desaturation events per hour of sleep. • Limb Movement Index: The number of limb movement events per hour of sleep. • Periodic Limb Movement Index: The number of periodic limb movement events per hour of sleep.
- Electroencephalography is typically based on electrodes placed on the scalp of the subject. The clinical standards for PSG require that the recording of EEG signals is done with electrodes located on parts of the head typically covered in hair. But a patient or subject generally can’t or has difficulty applying the sleep study electrodes on himself, or at least has difficulty applying the sleep study electrodes on himself correctly. Therefore the patient must be assisted by a nurse or technician.
- HSAT Home Sleep Apnea Testing
- HSAT generally only focuses on respiratory parameters and oxygen saturation for diagnosing sleep apnea and sleep disordered breathing. HSAT does however not require EEG electrodes on the head or sensors that the patient can’t place on him himself. Therefore, the most common practice in HSAT is to hand the HSAT system to the patient over-the-counter in the clinic or send the HSAT system by mail to the patient and have the patient handle the hookup or placement of the HSAT system to himself. This is a highly cost-efficient process for screening for sleep apnea.
- HSAT systems and methods can provide an accurate indication of total sleep time (TST), for example, as described in US 2021/0085242A1, as described below they suffer from the significant inability to determine arousal or arousal-associated events, and therefore current HSAT systems and methods are not able to correctly classify all three types of apnea/hypopnea events of a respiratory event index (REI).
- TST total sleep time
- REI respiratory event index
- apnea is a respiratory event that is defined by a 90% reduction in airflow from baseline lasting at least 10 seconds.
- a “hypopnea” is defined as respiratory events where the reduction in airflow is between 30% and 90% from baseline and the reduction in airflow is associated with a 3% or 4% drop in blood oxygen saturation and/or a cortical arousal.
- Scoring of Apneas [0017] Scoring of Apneas 1. Score a respiratory event as an apnea when BOTH of the following criterial are met: a. There is a drop in the peak signal excursion by ⁇ 90% of pre-event baseline using an oronasal thermal sensor (diagnostic study), PAP device flow (titration study) or an alternative apnea sensor (diagnostic study). b. The duration of the ⁇ 90% drop in sensor signal is ⁇ 10 seconds. 2. Score an apnea as “obstructive” if it meets apnea criteria and is associated with continued or increased inspiratory effort throughout the entire period of absent airflow. 3.
- Note 2 If a portion of a respiratory event that would otherwise meet criteria for a hypopnea meets criterial for apnea, the entire event should be scored as an apnea. (For example, as shown in FIG.1, the longer duration, depicted by the white arrows in the nasal pressure channel, meets airflow criteria for a hypopnea, whereas the shorter duration, depicted by the black arrows in the oronasal thermal airflow channel, meets airflow criteria for an apnea.
- apnea or hypopnea event begins or ends during an epoch that is scored as sleep
- the corresponding respiratory event can be scored and included in the computation of the apnea-hypopnea index (AHI).
- AHI apnea-hypopnea index
- the peak signal excursions drop by ⁇ 30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative hypopnea sensor (diagnostic study).
- the duration of the ⁇ 30% drop in signal excursion is ⁇ 10 seconds.
- c. There is a ⁇ 3% oxygen desaturation from pre-event baseline or the event is associated with an arousal.
- 1B. Score a respiratory event as a hypopnea if ALL of the following criterial are met: a. The peak signal excursions drop by ⁇ 30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative hypopnea sensor (diagnostic study). b.
- the duration of the ⁇ 30% drop in signal excursions is ⁇ 10 seconds.
- c. There is a ⁇ 4% oxygen desaturation from pre-event baseline.
- Score arousal during sleep stages N1, N2, N3, or R if there is an abrupt shift of EEG frequency including alpha, theta and/or frequencies greater than 16 Hz (but not spindles) that lasts at least 3 seconds, with at least 10 seconds of stable sleep preceding the change. Scoring of arousal during REM requires a concurrent increase in submental EMG lasting at least 1 second.
- Note 1 Arousal scoring should incorporate information from the frontal, central, and occipital derivations.
- AASM HSAT Scoring Apneas From the AASM manual for the scoring of sleep and associated events, home sleep apnea test (HSAT) scoring rules for apneas (v2.6, “G. HSAT Respiratory Events Rules: Scoring Apnea Utilizing Respiratory Flow and/or Effort Sensors”): 1. Score a respiratory event as an apnea when BOTH of the following criteria are met: a. There is a drop in the peak signal excursions by ⁇ 90% of pre-event baseline using a recommended or alternative airflow sensor. b. The duration of the ⁇ 90% drop in sensor signal is ⁇ 10 seconds. 2.
- Score an apnea as “obstructive” if it meets apnea criteria and is associated with continued or increased inspiratory effort throughout the entire period of absent airflow. 3. Score an apnea as “central” if it meets apnea criteria and is associated with absent inspiratory effort throughout the entire period of absent airflow. 4. Score an apnea as “mixed” if it meets apnea criteria and is associated with absent inspiratory effort in the initial portion of the event, followed by resumption of inspiratory effort in the second portion of the event.
- AASM HSAT Scoring Hypopneas From the AASM manual for the scoring of sleep and associated events, home sleep apnea test (HSAT) scoring rules for hypopneas (v2.6, “H. HSAT Respiratory Events Rules: Scoring Hypopnea Utilizing Respiratory Flow and/or Effort Sensors”): 1A. If sleep is NOT recorded, score a respiratory event as a hypopnea if ALL of the following criteria are met: a. The peak signal excursions drop by ⁇ 30% of pre-event baseline using a recommended or alternative airflow sensor. b. The duration of the ⁇ 30% drop in signal excursions is ⁇ 10 seconds. c.
- the duration of the ⁇ 30% drop in signal excursions is ⁇ 10 seconds.
- c. There is a ⁇ 3% oxygen desaturation from pre-event baseline or the event is associated with an arousal. 2B. If sleep IS recorded, score a respiratory event as a hypopnea if ALL of the following criteria are met: a. The peak signal excursions drop by ⁇ 30% of pre-event baseline using a recommended or alternative airflow sensor. b. The duration of the ⁇ 30% drop in signal excursions is ⁇ 10 seconds. c. There is a ⁇ 4% oxygen desaturation from pre-event baseline.
- FIG.2 shows an example of a scored apnea followed by a desaturation and an arousal. It is not necessary to have desaturations or arousals to score an apnea.
- FIG.2 shows examples of scored hypopneas followed by desaturations and arousals.
- hypopnea events are marked with bars drawn above the flow signal and labeled “hypopnea”, which correspond to the reduction in flow during the hypopneas is marked by the reduction in the flow signal amplitude.
- Desaturation events are marked on top of the SpO2 signal in the first half of the figure, and are labeled as “desaturation event”.
- the arousal events (labeled “arousal”) are labeled in the squares on top of the C4-M1 and C3-M2 signals.
- RERA Respiratory Related Arousal
- Apneas are defined by the AASM as a 90% reduction in airflow. Hypopneas are defined as a 30% or more decrease in airflow followed by a 3 or 4% drop in blood oxygen saturation measured with a pulse oximeter or an arousal. RERAs are respiratory events that do not fulfill the criteria of apneas or hypopneas, and terminate in an arousal. [0038] SUMMARY [0039] The inventors of the present application have identified a significant problem that the scoring of hypopnea events in a conventional Home Apnea Sleep Testing (HSAT) sleep study is limited by the fact that electroencephalography (EEG) signals are not recorded.
- HSAT Home Apnea Sleep Testing
- EEG electroencephalography
- AHI apnea hypopnea index
- REI respiratory event index
- RDI respiratory disturbance index
- HSAT home sleep apnea tests
- AHI Apnea Hypopnea Index
- EEG electroencephalography
- the inventors of the present application have developed and disclose herein methods and systems that predict sleep arousals using non-brain signal groups, or in other words using signals not obtained from a brain-machine-interface (BMI), or methods and systems that predict sleep arousals or arousal-associated events, including but not limited to arousal-associated hypopnea, without requiring brain signal groups.
- BMI brain-machine-interface
- methods and systems are disclosed herein that predict sleep arousals or arousal-associated events using non-EEG signal groups. Methods and systems are disclosed herein that predict sleep arousals without requiring EEG signal groups.
- methods and systems using on an effective AI model tailored for HSAT that can predict or identify sleep arousals using non-brain signal groups, or in other words using signals not obtained from a brain-machine-interface (BMI).
- methods and systems using on an effective AI model tailored for HSAT that can predict sleep arousals or arousal-associated events using only non-EEG signal groups.
- methods and systems using on an effective AI model tailored for HSAT that can predict sleep arousals using only two non-EEG signal groups.
- methods and systems are provided that predict sleep arousals or arousal-associated events using respiratory signals without requiring brain signal groups.
- a non-invasive method and system are provided for determining an arousal or arousal-associated events of a subject.
- the method includes (1) obtaining one or more respiratory signals, the one or more respiratory signals being an indicator of a respiratory activity of the subject, (2) extracting features from the one or more respiratory signals, and (3) determining an arousal or an arousal-associated event of the subject based on the extracted features.
- a method and system for determining an arousal or an arousal-associated event in a sleep study of a subject, the method comprising: obtaining data from one or more body signals, the one or more body signals being non-brain signals; and determining an arousal or an arousal-associated event of the subject using the data from one or more body signals.
- FIG.1 shows an example of a hypopnea event.
- FIG.2 shows an example of a scored apnea followed by a desaturation and an arousal.
- FIG.3 shows examples of scored hypopneas followed by desaturations and arousals.
- FIGS.4a and 4b illustrate an example of respiratory inductance plethysmograph (RIP) belts.
- FIG.5 shows an example of a scored apnea followed by a desaturation and an arousal as determined according to a preferred embodiment.
- FIG.6 shows examples of scored hypopneas followed by desaturations and arousals as determined according to a preferred embodiment.
- FIGS.7A, 7B, and 7C show schematics of a subject sleeping with HSAT sleep study devices.
- FIG.8 illustrates a computing device configured to perform the method of determining arousals based on received data obtained from the subject of the sleep study.
- FIG.9 shows a structure of a single gated recurrent unit (GRU) unit.
- FIG.10 shows a diagram of the neural network.
- FIG.11 shows a flowchart depicting the various exclusion criteria and the final dataset values for validation of the disclosed method.
- FIG.12 shows a visual representation of how test and reference AHI were obtained in the validation of the disclosed method.
- FIG.13 shows a Bland Altman plot for the whole cohort.
- FIGS.14A and 14B show Bland Altman plots of the reference and test AHI for a) males (FIG. 14A) and b) females (FIG.14B).
- FIGS.15A, 15B, 15C, 15D, 15E, and 15F show Bland Altman plot of the reference and test AHI for all the different age groups: a) 18-25 years (FIG.15A), b) 26-35 years (FIG. 15B), c) 36-45 years (FIG.15C), d) 46-55 years (FIG.15D), e) 56-65 years (FIG.15E), and f) 65+ years (FIG.15F).
- FIGS.16A, 16B, and 16C show Bland Altman plot of the reference and test AHI for the different BMI groups: a) Normal (BMI ⁇ 25) (FIG.16A), b) Overweight (25 ⁇ BMI ⁇ 30) (FIG.16B), and c) Obese (BMI ⁇ 30) (FIG.16C).
- FIGS.17A and 17B show that the majority of data points were centered around the zero difference line for both groups with comorbidity and the group without a known comorbidity.
- FIGS.18A and 18B show a Bland-Altman plot showing agreement for individuals taking medication (FIG.18A) and individuals not taking medication (FIG.18B).
- FIG.19 show a flowchart used for defining the medication study population.
- FIG.20 shows an example of how the thoracic RIP signal changes in a period of REM sleep interrupted by an awakening and a period of non-REM sleep.
- FIGS.21A and 21C show the systematic underestimation of Home Apnea Sleep Testing (HSAT) Respiratory Event Index (REI) using current HSAT methods compared to Polysomnography (PSG) Apnea Hypopnea Index (AHI), and 21B and 21D show the significant improvement to accuracy of the Home Apnea Sleep Testing (HSAT) Respiratory Event Index (REI) using an embodiment of the non-brain, BodySleep analysis method as described herein.
- FIG.22 shows a method of obtaining results from a home sleep study (HSS) that are significantly improved to level of accuracy comparable to a PSG study.
- HSS home sleep study
- a sleep study including an arousal prediction, determination, or classification based on cardio or heart-related signals or body movement signals are often inaccurate, due to the dependency of cardio or heart-related signals to unrelated factors, such as cardiac condition, blood pressure, medication and other individual specific factors.
- an arousal or an arousal-associated event determination be performed in what may be termed a “body sleep study”, meaning a sleep study performed without using or at least without requiring features derived directly from the brain, that is without using or at least without requiring features obtained by a brain-machine interface (BMI), that translates neuronal activity of the brain into signals, such as an electroencephalogram (EEG).
- BMI brain-machine interface
- EEG electroencephalogram
- arousal or an arousal-associated event determination in a HSAT or sleep study not including EEG without using or at least without requiring features derived from the heart.
- a HSAT or sleep study not including EEG to perform an arousal determination based on measuring one or more features other than body movement signals, as an arousal or an arousal-associated event determination of a sleep study based on body movement signals can be inaccurate.
- an “arousal-associated event” or “arousal-associated events” are events that occur in a relation with or are correlated with an arousal. Such events can occur prior to an arousal, simultaneously with an arousal, or post or after an arousal.
- An event is associated with an arousal when an arousal causes the associated event, the associated event causes the arousal, or the arousal and the arousal associated event have a mutual cause.
- Such events can include, but are not limited to: a transition from sleep to awake state, when a transition from sleep to wake is preceded by an arousal or occurs at the same time as an arousal; a transition from NREM2 sleep to NREM1 sleep or a period of time within a transition from NREM2 sleep to NREM1 sleep, for example a 10 second epoch, a 20 second epoch, a 30 second epoch, or up to a 60 second epoch; a transition from REM sleep to NREM1 sleep; when an arousal interrupts stage REM sleep; a period limb movement of sleep (PLMS) or limb movement (LM) associated arousal; an arousal and a limb movement that occur in a periodic limb movement (PLM) series
- the body signals that is, the non-brain signals—are obtained by non- invasive means or sensors.
- a method, sensor, or procedure may be described as non-invasive when no break in the skin is created and there is no contact with the mucosa, or skin break, or internal body cavity beyond a natural body orifice.
- the term invasive may be used to describe a measurement that requires a measurement device, sensor, cannula, or instrument that is placed within the body of the subject, either partially or entirely, or a measurement device, sensor, or instrument placed on the subject in a way that interferes with the sleep or the regular ventilation, inspiration, or expiration of the subject.
- a measuring of esophageal pressure (Pes) which is considered the gold standard in measuring respiratory effort, requires the placement of a catheter or sensor inside the esophagus and is therefore considered an invasive procedure and is not practical for general respiratory measures.
- Non-invasive methods to measure breathing movements and respiratory effort may include the use of respiratory effort bands or belts placed around the respiratory region of a subject.
- the sensor belt may be capable of measuring either changes in the band stretching or the area of the body encircled by the belt when placed around a subject’s body.
- a first belt may be placed around the thorax and second belt may be placed around the abdomen to capture respiratory movements caused by both the diaphragm and the intercostal-muscles.
- the resulting signal is a qualitative measure of the respiratory movement. This type of measurement is used, for example, for measurement of sleep disordered breathing and may distinguish between reduced respiration caused by obstruction in the upper airway (obstructive apnea), where there can be considerable respiratory movement measured, or if it is caused by reduced effort (central apnea), where reduction in flow and reduction in the belt movement occur at the same time.
- areal sensitive respiratory effort belts provide detailed information on the actual form, shape and amplitude of the respiration taking place. If the areal changes of both the thorax and abdomen are known, by using a calibration, the continuous respiratory volume can be measured from those signals and therefore the respiratory flow can be derived. [0076] The inventors have developed a method and system for determining arousals or arousal-associated events based on or using breathing features, body activity features, or a combination of breathing and body activity features but excluding or at least not requiring brain features or cardio features.
- the method may be based on using only the signals from one or more respiratory inductance plethysmography (RIP) belts intended for measuring respiratory movements of the thorax and abdomen.
- FIGS.4a and 4b illustrate an example of respiratory inductance plethysmograph (RIP) belts.
- FIG.4a shows an example of the wave-shaped conductors in the belts
- FIG.4b shows the cross-sectional area of each belt, which is proportional to the measured inductance.
- Respiratory Inductive Plethysmography (RIP) [0078] Respiratory Inductive Plethysmography (RIP) is a method to measure respiratory related areal changes.
- stretchable belts 31, 32 may contain a conductor 34, 35 that when put on a subject 33, form a conductive loop that creates an inductance that is proportional to the absolute cross sectional area of the body part that is encircled by the loop.
- Conductors 34, 35 may be connected to signal processor 38 by leads 36, 37.
- Processor 38 may include a memory storage.
- RIP technology includes therefore an inductance measurement of conductive belts that encircle the thorax and abdomen of a subject.
- a respiratory signal may be obtained by the respiratory signal being received by a processor directly from the RIP belts, by a processor receiving a pre-processed respiratory signal that had originally been obtained from the RIP belts, or a respiratory signal may be obtained by a processor by the processor receiving a respiratory signal that was previously obtained from a subject and stored on a memory storage, either in a raw unprocessed form or in a pre-processed form, and subsequently obtained or received by the processor from the memory storage.
- the memory storage may be a separate device from the processor, may be hardwired to the processor, or the stored respiratory signal may be transmitted to the processor, for example, over a network or another communications connection (either hardwired, wireless, or a combination of hardwired or wireless) to a computer system that includes the processor.
- the respiratory signals may be analyzed in real time.
- conductors may be connected to a transmission unit that transmits respiratory signals, for example raw unprocessed respiratory signals, or semi- processed signals, from conductors to processing unit. Respiratory signals or respiratory signal data may be transmitted to the processor by hardwire, wireless, or by other means of signal transmission.
- Resonance circuitry may be used for measuring the inductance and inductance change of the belt.
- an inductance L and capacitance C can be connected together in parallel.
- the oscillation can however be maintained at a frequency close to the resonance frequency.
- the inductance L can be calculated by measuring the frequency f and thereby an estimation of the cross-sectional area can be derived.
- the method for determining arousals or arousal-associated events may also include using a signal from an activity sensor.
- arousals or arousal-associated events such as arousal- associated hypopneas
- breathing signals or breathing signals in combination with other body activity features but excluding or at least not requiring brain features or cardio features may also include using a signal from an activity sensor.
- Other Body Signals may include using other physiological signals to detect arousals or arousal-associated events.
- physiological signals may be used to confirm or corroborate arousals or arousal-associated events detected by respiratory inductance plethysmography (RIP), or other physiological signals may be used in combination with RIP signals to detect, determine, or predict arousals or arousal-associated events.
- one or more other physiological signals, different than RIP signals may alone be the basis of and used to determine arousals during a sleep study using a method similar to that relied on for the determination of arousals using RIP signals.
- an oximetry signal SpO2 signal
- Other signals may include, but are not limited to, accelerometer signals, audio signals, cardiovascular signals, oximetry, non-cardiac electrode potentials, signals indicating body position, video signals, temperature signals, peripheral arterial tone (PAT) measurements pulse, heart rate, heart rate variability, changes in pulse wave amplitude (PWA), changes in pulse transit time (PTT), and other cardiovascular signals, or galvanic skin response (GSR) or combinations thereof to detect arousals.
- PAT peripheral arterial tone
- PWA pulse wave amplitude
- PTT pulse transit time
- GSR galvanic skin response
- Software may be used to derive multiple respiratory parameters from those signals or to derive multiple respiratory parameters activity parameters from those signals, such as respiratory rate, delay between the signals, stability of the respiration and ratio of amplitude between the two belts.
- the parameters may then be fed into a computing system.
- the parameters are fed into an artificial neural network computing system that has been trained to predict arousals or arousal-associated events of the subject.
- An artificial neural network computing system may also be trained to predict the three sleep stages, Wake, REM and NREM, which may be used to plot a simplified hypnogram for the night.
- the classifier computing system might be different than an artificial neural network.
- a support vector machine (SVM) method could be used, clustering methods could be used, and other classification methods exist which could be used to classify epochs of similar characteristics into one of several groups.
- SVM support vector machine
- CNN convolutional neural network
- the inventors have developed a method (referred to by the Applicant Nox as “BodySleep2.0” but is also referred to herein simply as “BodySleep”) of detecting sleep and arousals or arousal-associated events using physiological signals other than EEG, or more generally physiological signals other than brain signals or using non-brain signal groups, or using physiological signals that are not obtained from a brain-machine-interface (BMI).
- RIP respiratory inductance plethysmography
- RIP respiratory inductance plethysmography
- RIP respiratory inductance plethysmography
- arousals following respiratory events, since it has been found that one signature of the termination of a respiratory event are large recovery breaths. Recovery breaths are large breaths following a period of reduced breathing. These breaths typically result in a larger amplitude swing in the measured flow signal than baseline and the breaths flow signals may also have distinct shapes.
- Other embodiments of the method may include using other physiological signals to detect arousals or arousal-associated events. Other physiological signals may be used to confirm or corroborate arousals detected by respiratory inductance plethysmography (RIP), or other physiological signals may be used in combination with RIP signals to detect, determine, or predict arousals.
- RIP respiratory inductance plethysmography
- Such other signals may include, but are not limited to, accelerometer signals, Peripheral Arterial Tona (PAT) measurements pulse, heart rate, heart rate variability, changes in pulse wave amplitude (PWA), changes in pulse transit time (PTT), and other cardiovascular signals, or galvanic skin response (GSR) to detect arousals.
- PAT Peripheral Arterial Tona
- PWA pulse wave amplitude
- PTT pulse transit time
- GSR galvanic skin response
- non-cardiac signals can be used to detect sleep stages for every predetermined period of the sleep study, for example, preferably every 30 second period or what may termed an epoch.
- the resolution of the study, or the length of the periods of the sleep study can be varied.
- the predetermined periods can be 10 minutes, 5 minutes, 3 minutes, 2 minutes, 60 seconds, 45 seconds, 30 seconds, 20 seconds, or even 10 seconds.
- every period for example, 30 second period (epoch)
- epoch 30 second period
- Other embodiments might classify different length periods into sleep stages, and the sleep stages of interest might be different such as Wake, light sleep, deep sleep, REM; or Wake, NREM 1, NREM 2, NREM 3, REM sleep, or any other sleep stages.
- the method of the present disclosure determines the probability of an arousal or an arousal-associated event occurring at a predetermined interval, such as at every second, and if the probability crosses a certain threshold for a given amount of time an arousal event is scored.
- the interval for the scoring of arousals may be varied, similar to the epochs for the sleep stage determinations, and may be 10 minutes, 5 minutes, 3 minutes, 2 minutes, 60 seconds, 45 seconds, 30 seconds, 20 seconds, or even 10 seconds, 5 seconds, 3 seconds, 2 seconds, 1 second, or less than 1 second, such as 3/4 second, 1/2 second, 1/4 second, or less. Different embodiments may implement this differently.
- the one second interval may be an arbitrary choice, and how long an interval or period the probability of an arousal has to be above a threshold can also be changed to meet the needs of the sleep study.
- CNN convolutional neural networks
- Other types of artificial neural networks may also be used.
- FIG.5 shows an example of a scored apnea followed by a desaturation and an arousal as determined according to a preferred embodiment.
- the apnea is marked with the orange square on top of the flow signal.
- the desaturation event is marked by the sea green square on top of the SpO2 signal, and the arousals are the sea green squares on top of the Activity signal.
- the arousals were scored with the current embodiment.
- FIG.5 also shows that each of the epochs are classified as NREM, NREM, and Wake sleep stages. This is illustrated below the timeline and above the row of “S” characters. There NREM is painted in sea green and wake in yellow.
- FIG.6 shows examples of scored hypopneas followed by desaturations and arousals as determined according to a preferred embodiment. The hypopnea events are marked with cyan bars drawn above the flow signal. The reduction in flow during the hypopneas is marked by the reduction in the flow signal amplitude. Desaturation events are labeled and marked with sea green squares on top of the SpO2 signal in the first half of the figure. The arousal events are the sea green squares on top of the Activity signal.
- FIG.6 also shows that each of the epochs are classified as NREM sleep stage. This is illustrated below the timeline and above the row of “L” characters. There NREM is painted in sea green.
- RERA Respiratory Related Arousal
- a Respiratory Related Arousal is a respiratory event that does not fulfill the criteria of apneas or hypopneas, that terminates in an arousal.
- Using the abdomen and thoracic RIP signals as input to a model one can determine changes in airflow. Applying the method of the above- described preferred embodiments to score arousals would allow directly scoring of the respiratory events, without outputting the arousals.
- apnea-hypopnea-index (AHI)
- AHI is the clinical parameter used to determine if a patient is eligible for sleep apnea treatment. To calculate the AHI uses the number of apneas and hypopneas and an estimation of the sleep time.
- One practice is to use the recording time as an estimate of the sleep time. This results in a parameter called the respiratory event index (REI).
- REI respiratory event index
- An index called the respiratory disturbance index (RDI) is the number of apneas, hypopneas, and RERAs per hour of sleep.
- RDI respiratory disturbance index
- the preferred methods disclosed herein may be used to directly predict the AHI classification, the AHI, or the respiratory events.
- Performance of Preferred Embodiments in First Validation [0102] According to the preferred embodiment, the method was first validated on 90 sleep recordings from a sleep clinic in the United States. Below are the results of the validation. [0103] Sleep stage classification in first validation [0104] As shown in Table 1-1 below, in a first validation process, two embodiments of the Nox BodySleep were validated. A first embodiment used the RIP, Activity, and signals from the pulse oximeter (Pulse Wave and SpO2) as inputs.
- a second embodiment used only the RIP and Activity signals as inputs.
- the outputs are labels for each 30 second period (epoch) in the sleep study.
- the performance of the embodiment was compared with the gold standard, manually scored polysomnography (PSG) sleep studies.
- PSG polysomnography
- a confusion matrix was constructed showing the epoch level agreement in the classification and the Sensitivity, Specificity, Accuracy, Matthews Correlation Coefficient (MCC), and F1 scores calculated.
- the performance of the arousal scoring was done by calculating the Sensitivity, Specificity, and Accuracy for the presence or absence of an arousal event within a 30 second epoch.
- the gold standard manual scoring of PSG sleep studies was used as the reference.
- the performance was validated for different detection thresholds of the arousal scoring.
- the performance of the method of this preferred embodiment was compared to the performance of the Noxturnal TM PSG arousal scoring model, which is a released medical device in Europe.
- Threshold Sensitivity Specificity 0 100 78 0.09 41 96 84 0.04 57 91 84 0.03 71 80 78 PSG model 67 91 86 RIP + Activity Arousals (Epoch level agreement) Threshold Sensitivity Specificity Accuracy 0.09 41 95 83 0.05 50 92 82 0.04 55 89 81 0.035 60 85 80 0.03 78 65 68 PSG model 67 91 86 [0106] Table 1-3 shows the arousal scoring was used to determine if a reduction in airflow during sleep is considered a Hypopnea.
- hypopnea scoring was used to calculate the Apnea-Hypopnea Index (AHI) which is an index of how many apneas and hypopneas occur during each hour of sleep (events / hour).
- AHI Apnea-Hypopnea Index
- Sleep apnea severity is classified using the AHI index.
- the gold standard manual scoring of PSG sleep studies was used as the reference. The performance was validated for different detection thresholds of the arousal scoring. The performance of the method of this preferred embodiment was compared to the performance of the Noxturnal TM PSG arousal scoring model. These results show that the method of this preferred embodiment improves the clinical outcomes of patients who undergo HSAT sleep studies that are based only on RIP signals (wherein no activity signal and no pulse oximeter signal is required or used) by improving the sensitivity and accuracy of the sleep apnea diagnosis.
- an HSAT sleep study with improved sensitivy and accuracy of the apnea diagnosis may be provided according to the disclosed methods and systems herein without requiring an activity signal such as an accelerometer or a pulse oximeter, which is a relatively expensive device, adds complexity to the sleep study, is prone to failure, and decreases comfort.
- the deep learning model performs a prediction for each recorded second (1-second intervals) and aggregates those results to score arousal events.
- a total of 2216 manually scored PSG sleep recordings were employed from various sleep centers in five countries.
- the model s robustness and accuracy was tested, using recordings from a separate sleep center that was not included in training or validation. Additionally, we ensured that the recordings covered all categorical severities of sleep apneas; i.e., normal, mild, moderate, and severe.
- the model compared with manual arousal scoring, using epoch- level agreement, the model exhibited a sensitivity, specificity, and accuracy of 62%, 86%, and 81%, respectively.
- AHI arousals or no arousals.
- the sensitivity, specificity, and accuracy was 95%, 100%, and 96%, respectively, with arousals, but 68%, 100%, 75% without.
- the metrics were 95%, 100%, and 96%, respectively, with arousals, but 54%, 100%, 80%, without.
- the metrics were 86%, 96%, 94%, respectively, with arousals, a 24% increase in sensitivity compared with not using arousals.
- ANN artificial neural network
- HSAT study the accuracy for apnea hypopnea index (AHI) analysis from HSAT study is on par and comparable with PSG results, even if only the RIP signals are being used for the AHI diagnoses.
- AHI apnea hypopnea index
- the aroussal and arousal-assocaited events detection methods described herein elevate the accuracy of respiratory analysis of arousals from being considered unusable without EEG reference, according to AASM, to provide accuracy on par with PSG scored arousals. Further, the disclosed method and system provides an effective way for detection for arousals and aroussal-associated events that are not apnea or hypopnea based nor based on sleep disordered breathing, but can be based on non-respiratory events such as PLMS or even external stimuli that arouse the subject.
- FIGS.7A, 7B, and 7C show schematics of a subject 400 sleeping with HSAT sleep study devices.
- the devices worn by the subject in such as study may include respiratory inductance plethysmography (RIP) belts 451, 452, arranged about the thoracic region and an abdominal region of the subject, respectively.
- the RIP belts 451 and 452 may transmit, e.g., wireless or through a wired connection, to a recording device 455 which obtains and stores the data of the RIP signals through the study.
- a further sensor 490 such as an accelerometer or other activity sensor may be applied to a limb or body portion of the subject, such as on the leg. Data obtained by the further sensor 490, such as activity, motion, or accelerometer data can also be transmitted to and recorded by recording device 455.
- Belts 451 and 452 may be disposable devices that would be disposed of by the subject after the sleep study is performed.
- the belts 451,452 may be configured to be worn for multiple nights, after which the belts can be disposed.
- Further sensor 490 may also be a disposable device.
- Recording device 455 need not necessarily be attached to belt 451. Recording device 455 may be returned to the home sleep study administrator and the RIP sleep data and the further sensor data obtained and stored therein may be downloaded or otherwise retrieved by the computer of the sleep study administrator.
- the recording device 455 may further include a memory and a memory storage, and may be provided with a mobile application to interact with and control the RIP belts 451, 452, and to receive data obtained by the belts and the further sensor.
- the recording device may further be configured to transmit the data in real time, or at the conclusion of the sleep study, or at a later time, through a network or otherwise wireless connection or over the internet, to a data receiving device of the sleep study administrator.
- separate recording devices 471, 472 may be provided to record the signals of the thoracic RIP belt 451 and the abdomen RIP belt 451, respectively.
- each separate recording device 471, 472 may be configured to record the data obtained from the respectively RIP belt 451,452 and may be either delivered physically or mailed back to the sleep study administrator.
- the recording devices 471,472 may be configured to transmit the data in real time, or at the conclusion of the sleep study, or at a later time, through a network or otherwise wireless connection or over the internet, to a data receiving device of the sleep study administrator.
- One or both of recording devices 471,472 may also receive and record and/or transmit data obtained from the signal of the further sensor 490.
- Recording device 455 or separate recording devices 471,472 may be power the RIP belts and may be rechargeable by the subject or patient.
- FIG.8 illustrates a computing device 1000 configured to perform the method of determining arousals of the subject during the sleep study and process the body-signal data (e.g., RIP data). The device 1000 can perform some or all of the steps discussed above.
- the device 1000 may perform arousal determination method using a utility application, background daemon, or component of an operating system, or combination thereof, executing in conjunction with CPU 1001 and an operating system such as Microsoft Windows 7, UNIX, Solaris, LINUX, Apple MAC-OS and other systems known to those skilled in the art.
- CPU 1001 may be a Xenon or Core processor from Intel of America or an Opteron processor from AMD of America, or may be other processor types that would be recognized by one of ordinary skill in the art.
- the CPU 1001 may be implemented on an FPGA, ASIC, PLD or using discrete logic circuits, as one of ordinary skill in the art would recognize.
- the device 1000 in FIG.8 also includes a network controller 1006, such as an Intel Ethernet PRO network interface card from Intel Corporation of America, for interfacing with a network 1030.
- the network 1030 can be a public network, such as the Internet, or a private network such as an LAN or WAN network, or any combination thereof and can also include PSTN or ISDN sub-networks.
- the network 1030 can also be wired, such as an Ethernet network, or can be wireless such as a cellular network including EDGE, 3G and 4G wireless cellular systems.
- the network 1030 can also be Wi-Fi, Bluetooth, or any other wireless form of a communication that is known.
- the device 1000 further includes a display controller 1008 for interfacing with a display 1010.
- a general purpose I/O interface 1012 interfaces with input devices 1014 as well as peripheral devices 1016.
- the general purpose I/O interface also can connect to a variety of actuators 1018.
- the input devices 1014 can include the various sensors, although additional sensors are not necessary for the system.
- the input devices 1014 may include an interface to receive data from a recording device 455 in FIG.7A, for example.
- a sound controller 1020 may also be provided in the device 1000 to interface with speakers/microphone 1022 thereby providing sounds and/or music.
- a general purpose storage controller 1024 connects the storage medium disk 1004 with a communication bus 1026, which may be an ISA, EISA, VESA, PCI, or similar, for interconnecting all of the components of the device 1000.
- a communication bus 1026 which may be an ISA, EISA, VESA, PCI, or similar, for interconnecting all of the components of the device 1000.
- Descriptions of general features and functionality of the display 1010, input devices 1014 (e.g., a keyboard and/or mouse), as well as the display controller 1008, storage controller 1024, network controller 1006, sound controller 1020, and general purpose I/O interface 1012 are omitted herein for brevity as these features are known.
- Instructions for the performance of the arousal determination method can be stored on computer storage media and performed using a computation/logic circuitry.
- Computer storage media are physical storage media that store computer- executable instructions and/or data structures.
- Physical storage media include computer hardware, such as RAM, ROM, EEPROM, solid state drives (“SSDs”), flash memory, phase- change memory (“PCM”), optical disk storage, magnetic disk storage or other magnetic storage devices, or any other hardware storage device(s) which can be used to store program code in the form of computer-executable instructions or data structures, which can be accessed and executed by a general-purpose or special-purpose computer system to implement the disclosed functionality of the disclosure.
- Transmission media can include a network and/or data links which can be used to carry program code in the form of computer-executable instructions or data structures, and which can be accessed by a general-purpose or special-purpose computer system.
- a “network” may be defined as one or more data links that enable the transport of electronic data between computer systems and/or modules and/or other electronic devices.
- program code in the form of computer-executable instructions or data structures can be transferred automatically from transmission media to computer storage media (or vice versa).
- program code in the form of computer-executable instructions or data structures received over a network or data link can be buffered in RAM within a network interface module (e.g., a “NIC”), and then eventually transferred to computer system RAM and/or to less volatile computer storage media at a computer system.
- a network interface module e.g., a “NIC”
- NIC network interface module
- computer storage media can be included in computer system components that also (or even primarily) utilize transmission media.
- Computer-executable instructions may comprise, for example, instructions and data which, when executed by one or more processors, cause a general-purpose computer system, special-purpose computer system, or special-purpose processing device to perform a certain function or group of functions.
- Computer-executable instructions may be, for example, binaries, intermediate format instructions such as assembly language, or even source code.
- the disclosure of the present application may be practiced in network computing environments with many types of computer system configurations, including, but not limited to, personal computers, desktop computers, laptop computers, message processors, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, mobile telephones, PDAs, tablets, pagers, routers, switches, and the like.
- the disclosure may also be practiced in distributed system environments where local and remote computer systems, which are linked (either by hardwired data links, wireless data links, or by a combination of hardwired and wireless data links) through a network, both perform tasks.
- a computer system may include a plurality of constituent computer systems.
- Cloud computing environments may be distributed, although this is not required. When distributed, cloud computing environments may be distributed internationally within an organization and/or have components possessed across multiple organizations.
- cloud computing is defined as a model for enabling on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services). The definition of “cloud computing” is not limited to any of the other numerous advantages that can be obtained from such a model when properly deployed.
- a cloud-computing model can be composed of various characteristics, such as on- demand self-service, broad network access, resource pooling, rapid elasticity, measured service, and so forth.
- a cloud-computing model may also come in the form of various service models such as, for example, Software as a Service (“SaaS”), Platform as a Service (“PaaS”), and Infrastructure as a Service (“IaaS”).
- SaaS Software as a Service
- PaaS Platform as a Service
- IaaS Infrastructure as a Service
- the cloud-computing model may also be deployed using different deployment models such as private cloud, community cloud, public cloud, hybrid cloud, and so forth.
- Some embodiments, such as a cloud-computing environment may comprise a system that includes one or more hosts that are each capable of running one or more virtual machines.
- Feature Extraction may be based on or include inputting the raw non-brain signal into the neural network as described above. Or alternatively, determination of arousal may be a two-part problem with the first step in the process being the extraction of features from the raw recordings.
- a feature extractor was written in Python 3.5.5 to perform this task. The extractor may rely on NumPy and/or SciPy. The output of the feature extractor is a comma-separated values (CSV) file where the rows represent each epoch and the columns contains the features.
- CSV comma-separated values
- the signals used are those derived from the abdomen and thorax RIP belts. These include the Abdomen Volume, Thorax Volume, RIPSum, RIPFlow, Phase, and RespRate signals. Additionally, an activity signal from an accelerometer was used. All the features were calculated over a 60, 30, 20, 10, 5, or 1 second interval.
- Abdomen Volume and Thorax Volume are the RIP signals recorded during the sleep study. The signals may be recorded using the respiratory inductance plethysmography (RIP) bands placed around or on the thorax and abdomen of the subject under study. The RIP signals represent volume in the abdomen and thorax during breathing.
- RIP respiratory inductance plethysmography
- RIPSum is a signal created by adding the samples of Abdomen Volume and Thorax Volume signals.
- the RIPSum signal is a time series signal of the same number of samples and duration in time as the Abdomen Volume and Thorax Volume signals.
- RIPFlow is the time derivative of the RIPSum signal.
- the RIPSum signal represents volume and the time derivative represents changes in volume which is flow.
- Phase is a signal that represents the apparent time delay between the recorded Abdomen and Thoracic volume signals. During normal unobstructed breathing the Abdomen and Thorax move together out and in during inhalation and exhalation.
- RespRate represents the respiratory rate of the subject under study.
- the respiratory rate is a measure of the number of breaths per minute and is derived from the Abdomen Volume and Thorax Volume signals.
- the main points in the description of feature extractor and the features extracted by the feature extractor are: - It works on the recorded signals of Abdomen RIP, Thorax RIP, and accelerometers. - It works on signals derived from the above-mentioned recorded signals. These are the RIPSum, RIPFlow, Phase, RespRate, and Activity. - It splits the signals into 30 second epochs which are used to calculate the features. - Is may be implemented in Python using NumPy and SciPy. This is not an essential feature of the method, just how it was done in in an embodiment. - It outputs results in a CSV file. This is not an essential feature of the method, just how it was done in an embodiment.
- the respiration features are calculated from the RIPSum, RIPFlow and RespRate signals. The features calculated were designed to give information about changes in the respiratory rate with various methods.
- the first harmonic and DC ratio is used to estimate respiratory rate variability. The first harmonic and the DC component are found in the frequency spectrum of a flow signal.
- the RIPFlow was used but some preprocessing required. Such preprocessing included before taking the Fourier transform of the signal, all positive values are made 0, which results in the signal being more periodic as the exhalation is more regular. This can be seen in FIG.3.
- the fast Fourier transform is applied on the resulting signal and the DC component and the first harmonic peak are located.
- the DC component is defined as the magnitude at 0 Hz and the first harmonic peak is the largest peak of the frequency spectrum after the DC ratio.
- the mean and standard deviation of the respiratory rate is calculated for each epoch.
- the breath-by-breath features are based on features which are calculated for each breath.
- the final features are then calculated by taking the mean, median or standard deviation of the breath features for each epoch.
- the breaths may be located by running a breath-by-breath analysis on the RIPsum signal of the whole recording to identify all the breaths.
- the breaths may then be divided between the 30s epochs, with breaths that overlap two epochs being placed in the epoch that contains the end of the exhalation of the breath.
- the signals used for the feature calculations are the RIPsum, RIPflow, Abdomen Volume and Thorax Volume.
- the breath-by-breath analysis may be based on a start of inhalation being marked as the start of a breath and the end of exhalation being marked as the end of a breath.
- Detecting individual breaths in a sleep recording can be done by using the abdomen RIP signal, the thorax RIP signal, or their sum (RIPsum).
- Breath onset is defined as the moment when the lungs start filling with air from their functional residual capacity (FRC) causing the chest and abdomen to move and their combined movement corresponding to the increase in volume of the lungs.
- Functional Residual Capacity is the volume of air present in the lungs at the end of passive expiration and when the chest and abdomen are in a neutral position.
- a RIPsum signal of breathing during sleep may be obtained. The RIPsum starts at a lower bound, End/Start, and rises to an upper bound, Midway point, before it falls back down.
- a naive or simple method of detecting the breath onset is to look for points where the derivative of the signal changes sign from negative to positive, or when the derivative crosses the zero value from negative to positive and label them as End/Start. Points where the sign of the derivative changes from positive to negative are the Midway points.
- this naive or simple method suffers from misidentification of End/Start points and Midway points in the presence of noise. [0161] In the presence of noise, too many points can be identified as End/Start points or Midway points. To mitigate this one can low-pass filter the signal at a frequency high enough to capture the breathing movement and low enough to remove most noise.
- a cutoff frequency of, for example, 3 Hz could be used, as it is around ten times higher than the breathing frequency.
- a second mitigation strategy is to investigate the End/Start points and Midway points and identify points which represent noise.
- One strategy to combine points is to define a threshold value in the signal amplitude which needs to be passed before defining a new End/Start point or a new Midway point.
- a correlation feature is based on the similarity of adjacent breaths. To evaluate their similarity the cross-correlation is used with the coefficient scaling method. The coefficient scaling method normalizes the input signals, so their auto-correlation is 1 at the zero lag.
- the cross-correlation is calculated for each adjacent pair of breaths and the correlation of the breaths is found as the maximum value of the cross-correlation.
- the last breath of the previous epoch is included for the correlation calculation of the first breath of the current epoch.
- the mean and standard deviation are then calculated over each epoch.
- the RIPSum signal is used for these calculations.
- the breath length for each breath is calculated along with the inhalation and exhalation durations. This may be done using the start, end and peak values returned by the breath finder. For each epoch then the mean and standard deviation of these lengths was calculated.
- the median peak amplitude of the RIPsum signal is also calculated for each breath over an epoch.
- the median volume and flow of the inhalation, exhalation and the whole breath are calculated for each breath and then the median of all breaths within each epoch is calculated. Along with that, the median of the amplitude of each breath is calculated and the median value of all breaths within each epoch is calculated. This results in 6 features.
- the zero-flow ratio is calculated by locating the exhalation start of each breath. The difference of the amplitude at exhalation and inhalation start is calculated for the abdomen and thorax volume signals and the ratio of the abdomen and thorax values are calculated for each breath. The mean and standard deviation of these values are then calculated for each epoch.
- the standard deviation over 30, 20, 10, 5, and 1 second interval is calculated and the maximum and minimum difference over 30, 20, 10, 5, and 1 second interval is as well calculated.
- the activity features may be calculated using the activity signal.
- the activity signal is calculated by ! "# ⁇ + % ⁇ Where x and y are the x and y the horizontal plane, of the 3D accelerometer signal.
- Some of the features use the Abdomen and Thorax Flow signals which were calculated by numerical differentiation from the volume signals.
- the features that use the breath-by-breath analysis use it in the same way as the breath features in the chapter 3.2.
- the mean and standard deviation of the RIPphase signal are calculated over each 30, 20, 10, 5, and 1 second interval.
- the first method is to construct a signal that has the given histogram and then use built-in skewness functions.
- the second method is based on calculating the skewness directly by calculating the third moment and the standard deviation using the histogram as weights.
- the skewness is then calculated with equation 3.4 [0173] This may be done for each breath and the mean and standard deviation of the breaths within one 30 second epoch are calculated. The skewness is calculated for the abdomen, thorax and RIP volume traces. The RIPSum may be used to obtain locations of each breath. [0174] The ratio of the maximum flow in inhalation and exhalation may be found by first subtracting the mean from the flow signal and then dividing the maximum of the signal with the absolute of the minimum of the signal.
- the mean of this ratio may be calculated over 30 second epochs. This ratio is both calculated for the abdomen flow and the thorax flow signals.
- the time constant of inhalation and exhalation may also be used as features for the classifier.
- Breath length features may also be included, which may be calculated for all volume signals and their corresponding flow signals. First, the peak of the breath is found as the maximum value of the breath. The start of the breath is then found as the minimum value on the left side of the breath and the end as the minimum value on the right side.
- the inhale, exhale and total length of each breath is then calculated.
- the breaths are fetched with the breath-by-breath analysis on the RIPSum signal. This results in total of 18 features, but of course more or less features may be used.
- Pre-Processing [0179]
- the CSV files with the features for each recording may be loaded up in Python. Before any training or classification is started, some pre-processing may be required or preferable. The pre-processing may involve normalizing the features for each recording, to make the features independent of the subject in question. For example, if we have subject A with heart rate of 80 ⁇ 5 bpm and subject B with heart rate 100 ⁇ 10, they cannot be compared directly.
- each feature takes the value of 0 ⁇ 1 and they are therefore independent of subjects and are comparable between sleep stages.
- the pre-processing also involves converting the labels from strings ('sleep-wake', 'sleep-rem', 'sleep-n1', sleep-n2', 'sleep-n3') to numbers (0, 1, 2, 2, 2).
- the five given sleep stages may thus be mapped to three stages: 0 - wake, 1 - REM, 2 - NREM.
- the labels are then one-hot-encoded as required by the neural network architecture.
- an epoch originally has the label 'sleep-n2', it will first be assigned the number 2, and then after one-hot encoding, the label is represented as [0, 0, 1].
- Classifier [0183] The use of neural networks was considered for the classification task, as neural networks are well suited to learn from large and complex datasets.
- the use of gated recurrent units (GRU) was considered as gating mechanism to make the classification more time and structure dependent.
- GRU is a special type of recurrent layer that takes a sequence of data as an input instead of a single instance. GRU provides the network to see the ability to capture the time variance of the data, that is it can see more than just the exact moment it is trying to classify.
- the structure of a GRU unit can be seen in FIG.9.
- the implementation and training of the neural network was performed in Python, using the Keras machine learning library, with TensorFlow backend. TensorBoard was used to visualize and follow the progress of the training in real-time.
- 5.1 – The architecture of the final classifier [0186] After experimenting with different neural network architectures and tuning hyperparameters, a robust classifier was converged on.
- the final classifier is a neural network, having three dense layers (each with 70 nodes), followed by a recurrent layer with 50 GRU blocks.
- the output layer of the network has of 3 nodes, representing for each timestep the class probabilities that the given 30 sec. input window belongs to the sleep stages wake, REM and NREM, respectively.
- a diagram of an example network can be seen in FIG.10 where n is the number of features fed to the network.
- the classifier may be simplified to a single neural network, with both dense layers and a recurrent layer, whereas the previous classifier was composed of two separate neural networks (a dense one and a recurrent one). Further, early stopping may be introduced to minimize training time and to help reduce overfitting.
- RNN Recurrent Neural Network a type of an artificial neural network which learns patterns which occur over time.
- An example of where RNNs are used is in language processing where the order and context of letters or words is of importance.
- LSTM Long-Short Term Memory a type of an artificial neural network which learns patterns which occur over time.
- the LSTM is a different type of an artificial neural network than RNN which both are designed to learn temporal patterns.
- GRU is Gated Recurrent Unit, a building block of RNN artificial neural networks.
- CNN Convolutional Neural Networks
- this disclosure should be not limited to a particular number of layers, number of units, the connection between layers, the types of layers (RNN, LSTM, Dense, CNN, etc.), activation functions, or other parameters that can be changed without reducing the performance of the model [0195]
- the subgroups considered for this study were demographics, comorbidities, and medication types.
- the disclosed “BodySleep” analysis was compared to manual scoring using percentage agreement, predictive values, cohen’s kappa, and 95% confidence intervals derived from bootstrapping. [0199]
- the analysis exhibited strong agreement with manual scoring of AHI classification across most subgroups. For AHI thresholds of 5, 15, and 30, the overall percentage agreement (OPA) was observed to be 95%, 92%, and 95% respectively. Predictive values were also strong, with a positive predictive value (PPV) of 97%, 96%, and 94% for the same AHI thresholds.
- Sleep can be divided into three stages: wakefulness, rapid eye movement sleep (REM), and non-rapid eye movement sleep (NREM). which is subdivided into three stages of N1-N3.
- REM sleep rapid eye movement sleep
- NREM sleep non-rapid eye movement sleep
- the brain activity slows down, and physical renewal occurs.
- REM sleep brain activity increases, but the muscles are mostly paralyzed.
- these sleep stages appear in a predictable cycle pattern throughout the night. This roughly 90–120 minute cycle can be influenced and disrupted by various factors, that decrease the quality of sleep. Sleep quality is influenced by a range of factors including diet, age, physical activity, medication, genetic factors, environmental factors, sleep duration, and sleep disorders.
- Sleep disordered breathing refers to a group of sleep disorders characterized by respiratory events that can occur during sleep. Those disorders include, but are not limited to, obstructive sleep apnea (OSA) and central sleep apnea (CSA).
- OSA is a common disorder of repeated upper airway collapse during sleep. A complete or partial collapse results in respiratory events of apnea or hypopnea, respectively. An apnea is defined as a 90% reduction in airflow for 10 seconds or more.
- Hypopnea is defined as ⁇ 30% reduction in airflow for 10 seconds or more, accompanied by either a ⁇ 3% oxygen desaturation or an arousal event.
- the severity of OSA is determined based on the apnea-hypopnea index (AHI), representing the average number of apneas and hypopnea events per hour of sleep.
- AHI apnea-hypopnea index
- the severity is determined by the American Academy of Sleep Medicine (AASM) where a score of fewer than 5 apneas per hour is considered a normal score, between 5 and ⁇ 15 apneas per hour indicates mild OSA, 15 to ⁇ 30 apneas per hour indicates moderate OSA, and ⁇ 30 apneas per hour indicates severe OSA.
- AASM American Academy of Sleep Medicine
- a type 2 study uses a portable PSG device, which is typically set up by a sleep technologist in a laboratory, at the patient’s home, or in some cases by the patients themselves using detailed guidelines.
- SAS Self-applied somnography
- HSAT+ an enriched HSAT test
- EEG frontal electroencephalogram
- EEG electrooculography
- Type 3 and 4 sleep studies include fewer channels.
- Type 3, also called a polygraph, consists of the same signals as a PSG study, excluding the EEG, EOG, electrocardiogram (ECG), leg electromyography (EMG), and chin EMG.
- Type 4 sleep studies narrow it further to only one to three channels. However, only one type of type 4 study has been accepted by the AASM as a definitive diagnostic tool. Table 2-1 provides an in-depth comparison of these sleep studies. Table 2-1: Comparison of measurements for different types of sleep studies Measurements Type 1 Type 2 Type 3 Type 4 At home X X X In a laboratory X Sleep technologist X Electro-encephalogram (EEG) X X / Electro-ocoulogram (EOG) X X / Electro-cardiogram (ECG) X / / Chin Electro-myography (EMG) X / / Leg Electro-myography (EMG) X X / Respiratory flow X X / / Nasal vs mouth breathing X X Respiratory movements (RIP belts) X X X Oxygen saturation X X X X X X X X X X Body position X X X / Video X Audio X / /
- EEG Electro- oculography
- ECG Electro-cardiogram
- EMG Electro-myography
- RIP Respiratory inductance plethysmography.
- HSAT machine learning
- Individuals with an AHI ⁇ 5 from an HSAT study may be invited for an in-lab PSG to confirm the absence of SDB.
- RDI Respiratory Disturbance Index
- the PSG is unquestionably a vital tool for patients with complicated comorbidities, to make a precise clinical diagnosis. Using new diagnostic techniques could, however, result in better use of the sleep laboratory’s current capacities for patients who need those resources. Smart diagnostic devices with built-in automatic data processing algorithms or analysis make it possible to detect SDB more precisely at home without using time-, personnel-, and cost-consuming PSG tests. The gap between the high prevalence of SDB and the limited diagnostic capabilities could be filled by improving the diagnostic accuracy of HSAT by using more sophisticated diagnostic methods than PSG. [0211] Deep learning with sleep studies [0212] Recent studies of automated sleep stages have shown promising results with ML algorithms across large and diverse patient populations. They utilize different classifiers and feature determination methods that have been trained on datasets with thousands of participants.
- Sleep staging is a time-consuming process that requires manual inspection by a sleep technician, in batches of 30-second epochs, of EEG, ECG, and EMG.
- the manually scored sleep staging is evaluated with inter-rater reliability as quantified by kappa ( ⁇ ) that reflects epoch-by-epoch agreement above chance.
- ⁇ kappa
- Using AI to determine sleep stages and score respiratory and movement events may reduce the time sleep technologists must spend on PSG scoring, allowing them to devote more time to patient needs.
- CNN convolutional neural networks
- An embodiment termed “Bodysleep2.0” An embodiment of the method disclosed herein, referred to as the Nox BodySleep TM 2.0 (Nox Medical, Iceland), is based on a deep learning algorithm, which may be based on a convolutional neural network developed by the inventors at Nox Medical, intended to classify 30- second epochs of a type 3 sleep study into the states of REM, NREM, and wake. The analysis was designed to predict changes in autonomic functions correlating with the different sleep stages and arousals. [0216] Examples of the algorithm extract data from actigraphy and respiratory inductance plethysmography (RIP) belts.
- RIP respiratory inductance plethysmography
- Demographics provide insights into population characteristics, enabling researchers to analyze trends and patterns to better understand the healthcare needs of a specific population. By collecting information about sex, age, and body mass index (BMI), it is possible to gain a better understanding of the potential limitations of algorithms that are being applied in healthcare settings. Studies have shown that OSA is more prevalent in males compared to females. Epidemiological studies of OSA excluded females until the early nineties. The prevalence of OSA symptoms seems to differ between males and females. Males generally have a higher snoring index compared to females, who less frequently report snoring.
- Another factor that can affect the prevalence of OSA is physiological properties like weight. Overweight and obesity are significant public health concerns worldwide and the body mass index (BMI) is widely used to measure it. Individuals with obesity are also more likely to have OSA, compared to individuals with lower BMI. Fat distribution in females tends to be more peripheral compared to males and settles around hips, buttocks, and thighs. Excess fat in males tends to accumulate more centrally on the abdomen and neck. The difference in fat distribution between sexes may be a factor in the variation in OSA prevalence, as more adipose tissue settling centrally and around the airway is related to an increased risk of OSA.
- OSA positive airway pressure
- Type 2 diabetes and OSA share risk factors of obesity and aging, and symptoms such as decreased sleep quality
- Type 2 diabetes may influence respiration and sleep patterns through autonomic dysfunction in upper airway stability.
- Autonomic neuropathy which is common in diabetes, may also affect breathing, in addition to other autonomic body functions.
- Asthma is an inflammatory condition of the airways that leads to episodes of wheezing, breathlessness, chest tightness, and coughing.
- Nocturnal asthma may affect respiration and movement signals, due to shortness of breath, variable expiratory airflow limitation, and nasal congestion from chronic rhinosinusitis, a common comorbidity with asthma.
- Seasonal allergies may affect respiration through nasal congestion and obstruction, as well as inflammation of the upper airway. Negative pressure in the pharynx from allergic rhinitis may increase nasal resistance, predisposing the upper airway to collapse. Additionally, nasal congestion associated with allergic rhinitis could cause sleep fragmentation, due to increased negative intrathoracic pressure swings interfering with respiration patterns.
- HF Heart failure
- CSA central sleep apnea
- Cheyne-Stokes respiration is the most common form of CSA, characterized by periodic cycles of crescendo-decrescendo breathing that result in apnea or hypopnea episodes.
- Hyperventilation, circulatory delay, and cerebrovascular reactivity have been found to occur during sleep in patients with HF, leading to respiratory instability. This change in respiratory patterns has been suggested to be due to increased respiratory control response to changes in partial pressure of carbon dioxide (PaCO 2 ).
- PaCO 2 partial pressure of carbon dioxide
- cardiovascular conditions such as atrial fibrillation, heart disease, and hypertension have a high comorbidity rate with SDB. While their influence on respiration or movement during sleep may not be explicit, these conditions are associated with heart rate variability and blood pressure fluctuations that could indirectly affect sleep quality and patterns. Since these conditions may alter sleep dynamics such as respiration or sleep patterns, it is essential that the usage of AI algorithms for sleep scoring is not only accurate for the broader public but also reliable for those with a comorbid condition.
- Medications [0230] Various medications drugs can have profound effects on sleep and its architecture. Beta-blockers are a large group of drugs commonly used to treat hypertension, coronary artery disease, and heart failure. Their effect on the body includes lowering heart rate, blood pressure, and cardiac output.
- Non-selective beta-blockers also tend to cause contraction of smooth muscles which can lead to bronchoconstriction, a tightening of the airways, in predisposed individuals. This could lead to increased respiratory effort.
- the effects of beta- blockers on sleep do seem to vary depending on studies and their specific properties.
- Antidepressants are another group of drugs that significantly impact sleep by altering physiological patterns of sleep stages, particularly in REM sleep. These include selective serotonin reuptake inhibitors (SSRIs), norepinephrine-dopamine reuptake inhibitors (NDRIs), serotonin antagonist and reuptake inhibitors (SARIs), and serotonin-norepinephrine reuptake inhibitors (SNRIs).
- Antidepressants can alter sleep quality through various mechanisms, including the activation of serotonergic 5-HT2 receptors and changes in noradrenergic and dopaminergic neurotransmission.
- BDZ Benzodiazepines
- a very recent systematic review of the literature on BDZ and its effects on sleep reported an increase in time spent in NREM stage 2, a decrease in NREM stage 3 and 4, and also a decrease in REM sleep time in individuals who use BDZ. These changes could potentially lead to concentration difficulties, memory impairment, and weight gain. Studies have also shown, via questionnaire, that withdrawal from BDZ use can improve sleep disturbances and daytime sleepiness over time. Furthermore, BDZ are also thought to affect the arousal threshold.
- BDZ did not depress respiration but also increased the respiratory arousal threshold resulting in a reduced sleep apnea risk and severity with these patients.
- Amphetamine (AMP), atomoxetine (ATX), and methylphenidate (MPH) are stimulant drugs. They are all sympathomimetic drugs that increase noradrenergic and dopaminergic transmission, which impacts blood pressure and heart rate.
- Opioids are known to promote respiratory instability. Opioid-induced CSA is today the second most common type of CSA and occurs in up to 24% of opioid users. Research has indicated that severe SDB, specifically CSA, is common in individuals undergoing long-term opioid therapy.
- BodySleep2.0 or simply as “BodySleep”
- AHI and AHI categories to manually scored PSGs and enriched home sleep apnea tests (HSATs+) on different subgroups.
- the subgroups include age, sex, BMI, and different comorbidities and medications.
- the objective of these investigations is to determine if the algorithm performs well compared to the reference method and if its performance is different in sub-groups that could require further investigations, and data collection, or be considered as a contra-indication.
- FIG.11 shows the general exclusion process for all groups: demographics, comorbidities, and medication, wherein PSG is a Polysomnography; HSAT is a Home Sleep Apnea Test; and AHI is a Apnea–hypopnea Index.
- PSG is a Polysomnography
- HSAT Home Sleep Apnea Test
- AHI is a Apnea–hypopnea Index.
- 363 recordings were excluded due to being less than 4 hours in bed.
- 30 records were excluded for missing scoring.
- 452 recordings were excluded for being under age 18.
- PSG branch remained with 2121 recordings with a mean AHI of 18.9 ⁇ 20.6.
- the HSAT branch began with 1330 recordings at 1105.
- 658 recordings were excluded for being in bed less than 4 hours.
- the average AHI after the additional exclusion was 19.9 ⁇ 21.1, 20.0 ⁇ 21.2, and 20.0 ⁇ 21.2 respectively for the categories.
- additional N 1490 recordings were excluded after the general exclusion criteria had been applied.
- a total of N 973 recordings were left to be validated.
- the average AHI was 15.2 ⁇ 22.3.
- the comorbidities subgroups and the number of individuals in each group can be seen in Table 2- 10.
- additional N 2081 individuals were excluded after the general exclusion criteria had been applied.
- a total of N 396 recordings were left to be validated.
- HSAT+ An enriched home sleep apnea test
- HSAT+ is a type of home sleep study with additional EEG consisting of one frontal electrode and one ocular electrode, where arousals are scored for more accurate hypopnea scoring.
- the reference AHI represents the AHI from manually scored PSGs and HSATs+.
- the test AHI was obtained by removing signals from the PSG and HSAT+ studies and only leaving RIP signals and actigraphy which were then scored by the BodySleep analysis, as disclosed herein. By reducing the PSG and removing signals like EEG, EOG, and ECG, the study resembles an HSAT.
- FIG.12 shows a visual representation 1200 of how test and reference AHI were obtained.
- 1210 shows the dataset with all recordings PSG/HSAT+.
- EEG, EOG, and EMG data are removed for the test branch.
- the dataset of the HSAT branch is reduced (i.e., “Reduced PSG”).
- an embodiment of the disclosed method was performed, termed “BodySleep2.0 Analysis”, following the methods and using the system described herein.
- an automatic respiratory analysis was performed.
- Test AHI was produced.
- regular PSG/HSAT+ branch begins at 1220.
- the recordings of the full PSG/HSAT+ dataset are manually scored at 1230, at 1240 an automatic respiratory analysis is performed.
- Negative Predictive Value evaluates the proportion of negative AHI ⁇ 5 test results that truly are negative based on OSA prevalence in the general population.
- Bootstrapping was used to build a sampling distribution to calculate the 95% confidence intervals for different subgroups. Sampling was done on the sleep study level. Additionally, Bland-Altman plots and Cohen ⁇ s Kappa were used to assess the level of agreement or reliability between the reference method and an embodiment of the algorithm disclosed herein, the BodySleep2.0 algorithm, and the F1 score was used to evaluate the accuracy and reliability of the classification models’ performance.
- Table 2-2 displays descriptive statistics for all the eligible individuals after applying the above-mentioned exclusion criteria.
- Table 2-3 Agreement on AHI severity classification for AHI ⁇ 5, AHI ⁇ 15 and AHI ⁇ 30 PPA [%] NPA [%] OPA [%] AHI ⁇ 5 96 [95, 97] 91 [89, 94] 95 [94, 96] AHI ⁇ 15 87 [85, 89] 97 [96, 98] 92 [91, 93] AHI ⁇ 30 85 [82, 88] 99 [98, 99] 95 [95, 96] PPV: Positive predictive value; NPV: Negative predictive value; AHI: Apnea-Hypopnea Index; CI: Confidence interval.
- Predictive value [0261]
- Table 2-4 displays the initial PPV and NPV values along with their corresponding 95% confidence intervals obtained through bootstrapping. The confidence intervals for both statistics have very high limits for all thresholds. As the AHI thresholds increased, there was a slight decrease in limits for PPV accompanied by an increase for NPV.
- Table 2-4 Predictive value on AHI severity classification for AHI ⁇ 5, AHI ⁇ 15 and AHI ⁇ 30 PPV [%] NPV [%] AHI ⁇ 5 97 [97, 98] 87 [84, 89] AHI ⁇ 15 96 [95, 97] 89 [88, 91] AHI ⁇ 30 94 [92, 96] 96 [95, 97] PPV: Positive predictive value; NPV: Negative predictive value; AHI: Apnea-Hypopnea Index; CI: Confidence interval. [0263] To visualize the agreement between the reference method and the one obtained by the algorithm a Bland-Altman plot was created.
- FIG.13 shows a Bland Altman plot for the whole cohort.
- Table 2-5 summarizes Cohens ⁇ s Kappa values and F1 scores that were obtained for different AHI severity. Cohen’s kappa increased as the AHI increased and ranged from 0.84 to 0.87. The opposite happened to the F1, the score decreased with a higher AHI. It went from 0.96 to 0.89 as the AHI severity decreased.
- Table 2-5 Comparison of Cohen’s Kappa and F1 Score for different AHI severity Condition Cohen’s Kappa F1 Score AHI ⁇ 5 0.84 0.96 AHI ⁇ 15 0.85 0.91 AHI ⁇ 30 0.87 0.89 [0265] Confusion Matrices [0266] Table 2 - 6, show the confusion matrices for AHI thresholds of greater than 5, 15, and 30. They show the true positive (TP), false positive (FP), true negative (TN), and false negative (FN) classifications of different AHI thresholds when the reference AHI scores and the test AHI scores were compared.
- Table 2-6 Confusion Matrices for AHI ⁇ 5, AHI ⁇ 15, and AHI ⁇ 30 Test method A HI ⁇ 5 AHI ⁇ 5 Reference AHI ⁇ 5 1797 82 method AHI ⁇ 5 50 534 Test Method A HI ⁇ 15 AHI ⁇ 15 Reference AHI ⁇ 15 1010 149 method AHI ⁇ 15 41 1263 Test Method AHI ⁇ 30 AHI ⁇ 30 Reference AHI ⁇ 30 468 85 method AHI ⁇ 30 28 1882 [0267] Demographics [0268] The following table shows the number of individuals in different subgroups for sex, age, and BMI.
- Table 2-7 Number of the individuals in different subgroups, mean values G ender Size [N] Age [years] Height [cm] Weight [kg] BMI [kg/m 2 ] Female 1062 47.9 165.6 83.4 30.8 Male 1264 52.0 181.1 101.6 31.7 B MI Size [n] Age [years] Height [cm] Weight [kg] BMI [kg/m 2 ] Normal 504 41.8 178.1 64.0 Overweight 682 53.1 172.9 82.2 27.4 Obese 1140 51.4 172.8 112.7 37.7 Age Groups Size [N] Age [years] Height [cm] Weight [kg] BMI [kg/m 2 ] 18-25 261 20.8 170.2 76.4 26.4 26-35 267 30.2 171.9 96.7 32.6 36-45 404 40.3 174.0 97.1 32.3 46-55 513 50.5 176.9 100.1 33.1 56-65 430 59.5 174.5 95.3 31.7 >65 451 71.9 173.7 88.0 29.7 BMI: Body Mass Index [0269] Bla
- FIGS.14A and 14B show Bland Altman plots of the reference and test AHI for a) males (FIG. 14A), and b) females (FIG.14B).
- FIGS.15A–15F show Bland Altman plot of the reference and test AHI for all the different age groups: a) 18-25 years (FIG.15A), b) 26-35 years (FIG.15B), c) 36-45 years (FIG.15C), d) 46-55 years (FIG.15D), e) 56-65 years (FIG.15E), and f) 65+ years (FIG. 15F).
- FIGS.16A–16C show Bland Altman plot of the reference and test AHI for the different BMI groups: a) Normal (BMI ⁇ 25) (FIG.16A), b) Overweight (25 ⁇ BMI ⁇ 30) (FIG.16B), and c) Obese (BMI ⁇ 30) (FIG.16C).
- Agreement [0275] In this section are the agreement values for the different groups: Sex, age, and BMI. Table 2-8 shows the values of the agreement statistics (PPA, NPA, and OPA) for all subgroups along with their respective 95% CI from bootstrapping.
- Table 2-8 Agreement on AHI severity classification for AHI ⁇ 5 for males and females in the PSG and HSAT+ dataset Sex PPA [%] NPA [%] OPA [%] Male 97.2 [96.2, 98.2] 92.8 [89.8, 95.5] 96.2 [95.2, 97.2] Female 93.5 [91.8, 95.2] 89.8 [86.2, 93.1] 92.5 [90.9, 94.1] Age groups PPA [%] NPA [%] OPA [%] 18-25 92.7 [88.8, 96.2] 90.1 [82.6, 96.6] 92.0 [88.5, 95.3] 26-35 92.9 [89.2, 96.3] 82.5 [71.9, 92.0] 90.7 [87.2, 94.1] 36-45 92.7 [89.6, 95.5] 88.9 [81.6, 95.0] 91.9 [89.1, 94.4] 46-55 96.7 [94.8, 98.3] 93.5 [88.7, 97.5] 95.9 [94.2, 97.5] 56-65 98
- Table 2-9 Predictive values for each sex group for AHI ⁇ 5 in the PSG and the HSAT+ datasets Sex PPV [%] NPV [%] Male 97.9 [96.9, 98.7] 90.7 [87.3, 93.6] Female 96.4 [95.1, 97.6] 82.5 [78.1, 86.6] Age group PPV [%] NPV [%] 18-25 96.2 [93.0, 98.8] 82.1 [73.0, 90.3] 26-35 95.1 [92.1, 98.0] 75.8 [64.6, 86.2] 36-45 96.7 [94.4, 98.5] 77.7 [69.2, 85.4] 46-55 97.9 [96.4, 99.2] 89.8 [84.6, 94.7] 56-65 99.1 [97.9, 100.0] 94.4 [89.5, 98.2] >65 99.4 [98.4, 100.0] 94.9 [90.4, 98.3] BMI severity group PPV [
- Table 2-10 Means of comorbidity subgroups Subgroup Size [N] Age [years] Height [cm] Weight [kg] BMI [kg/m 2 ] ADHD 22 32.8 174.6 94.1 30.2 Anxiety 10 60.3 172.1 95.0 32.3 Asthma 46 41.1 170.8 97.4 33.4 Atrial fibrillation 59 64.0 172.6 90.3 30.2 Diabetes 59 46.6 171.9 107.7 36.3 Heart disease 46 64.0 174.6 101.8 33.2 Heart failure 13 62.3 173.9 112.9 37.1 Hypertension 217 56.4 174.3 108.6 35.7 Low testosterone 44 50.3 188.8 103.7 32.4 Obesity 1213 51.4 173.0 112.5 37.6 Gastrointestinal reflux 255 53.5 171.6 93.8 31.7 Seasonal allergies 58 30.3 177.3 116.5 37.1 Seizures 19 40.2 171.3 86.6 29.2 ADHD: Attention deficit hyperactivity disorder; BMI: Body mass index.
- FIGS.17A and 17B show that the majority of data points were centered around the zero difference line for both groups with comorbidity and the group without a known comorbidity. The mean difference for both groups was similar and the same applies to the standard deviation. Data points outside the limits of the agreement could be potential outliers. The distribution of the differences between the two methods was similar for all subgroups. There was no clear consistent bias where the differences were predominantly above or below zero.
- FIGS.17A and 17B show a Bland-Altman plot showing agreement for individuals with some comorbidity (FIG.17A) and individuals without known comorbidities (FIG.17B).
- Table 2-11 shows the PPA, NPA, and OPA for each comorbidity as well as the 95% CI from bootstrapping.
- the limits of the CIs for PPA were overall high.
- the lower bound of the CI was the lowest, or 66.7%, and for the low testosterone group, or 84.0%.
- Other comorbidity groups had a lower bound around 90.0% that ranged in many cases to 100.0%.
- Regarding the NPA the lower bounds of the CIs were lowest for heart failure, seasonal allergies, ADHD, and anxiety.
- the OPA was high for all the groups and the lower bound of the CI was over 85%, except for anxiety and heart failure.
- the upper bounds of the CIs were high in all cases.
- Anxiety had the lowest PPV value of 85.7% with a 95% CI of [50-100]% and a NPV of 100.0% with a 95% CI of [0.0-100.0]%. This could be explained by the lack of individuals with anxiety. The highest PPV was 100.0% with a 95% CI of [100-100] % for ADHD, asthma, atrial fibrillation, diabetes, low testosterone, and seizures. These high values could also be explained by the lack of individuals with AHI ⁇ 5 and the comorbidities mentioned above.
- Table 2-12 Predictive value - Positive Predictive Value (PPV) and Negative Predictive Value (NPV) Medication PPV [%] NPV [%] ADHD 100.0 [100.0, 100.0] 100.0 [0.0, 100.0] Anxiety 85.7 [50.0, 100.0] 100.0 [0.0, 100.0] Asthma 100.0 [100.0, 100.0] 100.0 [100.0, 100.0] Atrial fibrillation 100.0 [100.0, 100.0] 66.7 [25.0, 100.0] Diabetes 100.0 [100.0, 100.0] 81.8 [55.6, 100.0] Heart disease 94.3 [85.3, 100.0] 90.9 [71.4, 100.0] Heart failure 90.0 [66.7, 100.0] 66.7 [0.0, 100.0] Hypertension 97.6 [95.0, 99.5] 93.9 [86.4, 100.0] Low testosterone 100.0 [100.0, 100.0] 85.7 [66.7, 100.0] Obesity 98.9 [98.1, 99.6] 92.6 [89.3, 95.3] Gastrointestin
- Bland-Altman To visualize the difference in agreement between the BodySleep analysis method as disclosed herein and the reference method, two Bland-Altman plots were made, one for individuals taking any medication and another one for individuals who did not. The plots, which can be seen in FIGS.18A and 18B, which show that most of the observations were inside the limit of the agreement, with fewer observations outside the agreement for medication takers. FIGS.18A and 18B show a Bland-Altman plot showing agreement for individuals taking medication (FIG.18A) and individuals not taking medication (FIG.18B).
- Table 2-18 Characteristics of the individuals in different subgroups, mean values Subgroup AHI [/h] Arousals [/h] Respiratory events [/h] TST [min] ADHD 21.3 7.5 13.9 355.2 Anxiety 18.9 4.0 14.8 443.4 Asthma 16.3 4.7 11.6 352.8 Atrial fib 28.3 11.2 17.0 368.4 Diabetes 25.9 6.1 19.8 334.7 Heart disease 23.7 8.4 15.3 332.2 Heart failure 17.8 7.0 10.8 333.6 Hypertension 24.4 8.5 15.9 338.4 Low testosterone 22.3 8.6 13.8 342.1 Obesity 23.2 7.7 15.6 342.8 Reflux 17.6 4.2 13.5 337.8 Seasonal 31.2 10.6 20.6 371.7 Seizures 17.0 6.0 10.9 351.9 Table 2-19: Characteristics of the individuals in different subgroups, mean values Subgroup Min AHI Max AHI Mean AHI Median AHI STD AHI ADHD 0.0 115.6 21.3 10.7 26.8 Anxiety 1.8 46.9 18.9 12.8 17.7
- Table 2-21 Characteristics of the individuals in different subgroups, mean values Subgroup Min AHI Max AHI Mean AHI Median AHI STD AHI BDZ 0.0 104.1 16.2 8.5 21.7 Beta-blockers 0.0 108.2 24.5 16.0 25.5 NDRI 0.0 114.2 19.4 13.2 21.3 Opioids 0.0 86.9 20.8 16.3 21.4 SARI 0.0 79.7 14.7 9.2 17.9 SNRI 0.0 125.4 23.1 12.8 28.9 SSRI 0.0 91.2 17.0 9.8 19.5 Stimulants 0.0 108.2 11.3 5.6 19.4 [0299] Confusions Matrices: To aid in the understanding of the data set considered herein, the following confusions matrices are provided. Table 2-22: Confusions Matrix for males Table 2-23: Confusions Matrix for females
- Table 2-28 Confusion Matrix the age group 26-35
- Table 2-30 Confusion Matrix the age group 46-55
- Table 2-31 Confusion Matrix the age group 56-65
- Table 2-32 Confusion Matrix the age group > 65
- Table 2-33 Confusion Matrices for all comorbidities (a-m)
- Table 2-34 Confusion Matrix for BDZ Table 2-35: Confusion Matrix for Beta-blockers Table 2-36: Confusion Matrix for NDRI Table 2-37: Confusion Matrix for Opioids
- the confidence intervals for the agreement statistics showed that the Nox BodySleep2.0, in general, performs well compared to the reference method for all subgroups.
- the greater upper and lower bounds and smaller ranges observed in males may suggest that the algorithm performs slightly better for males compared to females.
- the increase of confidence interval bounds, for PPA, NPA, and OPA, with older age could mean that the Nox BodySleep2.0 performs better on recordings from individuals as they get older.
- increasing the limits of all confidence intervals with a higher BMI could imply the Nox BodySleep2.0 performing slightly better with a higher BMI.
- the predictive value statistics showed a similar trend.
- the BodySleep method as disclosed herein i.e., the Nox BodySleep2.0
- the BodySleep method as disclosed herein in the embodiment referred to as the Nox BodySleep2.0, can be used with confidence to more accurately estimate AHI severity in HSAT studies.
- FIGS.21A and 21C show the systematic underestimation of Home Apnea Sleep Testing (HSAT) Respiratory Event Index (REI) using current HSAT methods compared to Polysomnography (PSG) Apnea Hypopnea Index (AHI), and 21B and 21D show the significant improvement to accuracy of the Home Apnea Sleep Testing (HSAT) Respiratory Event Index (REI) using an embodiment of the non-brain, BodySleep analysis method as described herein.
- HSAT Home Apnea Sleep Testing
- REI Respiratory Event Index
- AHI is calculated as the count of (Apnea;Hypopnea with Desat;Hypopnea with Arousal)/Total Sleep Time
- REI is calculated as the count of (Apnea; Hypopnea with Desat)/Recording Time. It is noted that hypopneas are only counted once, even if they fulfill both the Desat and Arousal criteria.
- Total Sleep Time is typically measured with EEG, which is missing in the regular HSAT study. Therefore the accepted standard is to use Recording Time as the maximum approximation, which systematically drives down the REI compared with AHI.
- the HSAT should be considered “inconclusive" as the AHI could have been above the threshold. This means that for some patients, (especially women and kids) all the apneas/hypopneas may not meet the criteria captured by the HSAT, but all would be arousal based. This would make the HSAT deliver a REI of 0 but AHI of 50 as an example. So the correlation is 100% for Apneas and Hypopneas with Desat as they were determined in the same way on the same signals, but 0 on the arousal based.
- FIGS.21B and 21D show the HSAT performed according to the disclosed method wherein arousals and arousal-associated event are determined based on body signals (in this case RIP signals from 2 RIP belts, in a study of 643 sleep studies and 2,407 sleep studies respectively.
- body signals in this case RIP signals from 2 RIP belts, in a study of 643 sleep studies and 2,407 sleep studies respectively.
- FIG.21B the patient level agreement for AHI ⁇ 5 are shown in Table 3-1 below.
- Table 3-1 [0323]
- the patient level agreement for AHI ⁇ 15 are shown in Table 3-2 below.
- FIGS.21C and 21D show a similar validation of 2,407 studies, when using HSAT (with no EEG signal) and without an arousal detection as described herein, 1,937 (81%) subjects get the correct outcome, comparing the measured HSAT REI with the actual PSG AHI. However, when using the body-sleep based RIP signals and the methods described herein to determine arousals and arousal-associated events, 2,211 (92%) subjects get the correct outcome and the sleep studies and REI of 274 individuals (11%) are properly and correctly assessed. [0325] In FIG.21D, the patient level agreement for AHI ⁇ 5 are shown in Table 3-3 below.
- Table 3-3 [0326] In FIG.21D, the patient level agreement for AHI ⁇ 15 are shown in Table 3-4 below.
- Table 3-4 [0327] Ased used in Tables 3-1 to 3-4, "No Arousals" simply means that these are the standard HSAT results without a determination of body-signal or body-based arousal or arousal-associated events, or in other words that is not counting the arousal based hypopneas.
- the Afib- is a shortcut for Afibrillation that is a common cardiac condition. So the Afib dataset consists of patients undergoing a sleep study that have additionally this Afib- condition (Irregular heartbeat).
- the systems, sensors, and methods described herein provide a method 2200 of obtaining results from a home sleep study (HSS) that are significantly improved to level of accuracy similar to a PSG study.
- HSS home sleep study
- a request is received for a home sleep study (HSS).
- HHSS home sleep study
- Such a request may be received over the Internet or through a network.
- delivery of a HHS sensor is arranged.
- the HHS sensor is delivered to the subject. This may be through a common carrier or delivery, often to the home of the subject.
- the HHS sensor is applied to the subject.
- the HHS sensor includes a RIP belt sensor system including one or more, preferably two, RIP belts, including a thoracis RIP belt and an abdomen RIP belt, as shown, for example, in one of FIGS.7A–7C.
- HSS data is obtained by the HHS sensor. This data may be stored by the HHS sensor, or may be transmitted to a central server or computing device through a Bluetooth transmission, LAN, or cellular network, or the Internet. Or, the HHS sensor or a data storage device can be mailed, shipped, or delivered by carrier to a remote location housing the central server or computer device.
- a BodySleep is implemented including determining an arousal of the subject using the data from one or more body signals.
- a result is provided based on the RIP data including the determined arousals.
- a sleep therapy can be prescribed or implemented, a therapy can be modified based on the BodySleep analysis results.
- the method of 2200 provides for a high-quality HSS with results very comparable to a PSG without requiring clinical involvement in delivery or operation of the HSS.
- the HSS can be performed entirely by the subject and the HSS data can be uploaded to the Cloud or Internet, and can be analyzed and the results can be provided to the subject, for example, in a web accessible platform.
- the device shipped or delivered to the subject may include a recorder with one or more or preferably two RIP belts.
- the device delivered may also or alternatively include an accelerometer, or could be two devices, one on each RIP belt and a separate acceleration meter OR only two belts.
- the RIP belts may be reusable for multiple nights.
- the device may come with a Mobile Application or other "Receiving Unit", that has a wireless connection to the Device (Devices) for receiving the recorded RIP signals and acceleration signals (if included) in real time OR delayed during the night OR upload after the night.
- the Mobile Application may establish a link to the Cloud or over the Internet, for uploading the recorded data OR the Mobile Application run the BodySleep analysis on the data OR the "Receiving Unit” may upload or perform the BodySleep analysis.
- a set of sleep parameters are derived, such as sleep profile, arousals, sleep disordered breathing parameters, arousal index, and/or sleep stability measures.
- the device may be wireless and rechargeable by the patient.
- the device may be activated when the RIP belts are snapped around the patient and deactivated after removal from the patient.
- the HSS data from the recording may be presented to a person operating in patient care management and/or to the patient himself.
- the data from the recording may be used to determine if a sleep therapy is effective, needs adjustment and guide how to adjust the therapy.
- the results from the processing may be presented to a healthcare professional for diagnosis of a sleep disorder, confirmation of health sleep or monitoring of treatment performance.
- the RIP signals and optionally an acceleration signal is received and analysis according to the BodySleep analysis methods described herein.
- An arousal and sleep profile can be provided as additional parameters for scoring a HSAT recording.
- An accurate measure of standard Sleep Disordered Breathing condition can be provided that is compared to AASM PSG performance.
- Alternative parameters can be provided from the HSAT study such as endotypes that would normally require PSG. Results in a conclusive diagnosis of SDB from HSAT that would normally require PSG recording.
- Quality Assurance of HSAT using BodySleep analysis methods [0338] Instead of relying on using BodySleep analysis methods described herein for diagnoses, it can be used for qualifying HSAT recordings.
- a normal HSAT diagnosis may be performed, which as was the state of the art before the filing of the present disclosure, hypopneas and/or arousals are missed.
- the BodySleep analysis automation is performed and compared with the HSAT. In case of significant difference the study is determined as inconclusive and the patient is sent to PSG for a conclusive measurement.
- a new type of processing signals from PSG Same as above for HSAT analysis, but the results of teh BodySleep analysis methods work as surrogate signals for standard PSG signals, such as if the EEG signals are of bad quality etc.
- CPAP Continuous Positive Airway Pressure
- Unmanaged therapy has demonstrated over 50% non-compliance in the first year in multiple studies over the years.
- a managed therapy has however been demonstrated by the Applicant and the inventors to over 90% adherence, thanks to continuous monitoring on performance over radio modules in the CPAP's and high- quality service by care managers. Similar to having a personal trainer for exercise, the care- managers use a preemptive approach to spot patients struggling and adjust their therapy to be effective again.
- This model however, only supports CPAP units with a radio module, but alternative therapies such as oral appliances therapy (OAT), do not support this option.
- OFT oral appliances therapy
- CPAP devices Sleep care management using CPAP devices is based on data measured by the CPAP and delivered over radio modules to the cloud.
- the CPAP is, however, only in an indirect connection to the patient, the CPAP only "sees" the patient through the air-tube between the CPAP and the patient, based on the air-pressure and air-flow signals. Even if this gives the PAP device significant information on how well the patient is breathing, it cannot provide much information regarding how well the patient sleeps.
- a recording of a few night using a sensor device as described herein both provides the information how well the patient slept during those nights on treatment, but also information how to interpret the data from the CPAP up to the point of the BodySleep2.0 sensor recording and from that time one. This could improve the reliability of the data that the care managers have to work with and provide valuable and early warning if the patient's performance starts to degrade, that would eventually lead to the patient stopping using the therapy.
- the systems, sensors, and methods described herein can be a fundamental building block in an inexpensive sensor device (such as a 2-belt RIP sensor device) that can be used by patients to monitor the performance of the treatment they receive for their sleep disorders.
- the device can be shipped to the patient at some point in time and the patient can use the device with their treatment in their own home.
- the value of the systems, sensors, and methods described herein brings to the 2-belt sensor is that it allows the 2 belt sensor to detect sleep stages and arousals in the patient along with changes in breathing, such as apneas and hypopneas.
- Arousal scoring is particularly important since it allows the detection of hypopneas without requiring a measurement of drops in blood oxygen saturation (SpO2).
- the measurement of the SpO2 signal is measured by a pulse oximeter, which is a relatively expensive device, adds complexity to the sleep study, is prone to failure, and decreases comfort.
- the systems, sensors, and methods described herein e.g., as implemented in a Nox BodySleep2.0
- the RIP belt sensor e.g. a 2-belt RIP system
- the RIP belt sensor e.g. a 2-belt RIP system
- one method may include the following: At least a 2 RIP belt sensor (whcih may preferably be a single patient use), is sent to a customer on request.
- the patient downloads an app in his mobile phone that is paired with the sensor for wireless communications (such as BLE).
- the patient sleeps with the sensor that streams the recorded data either directly or buffered to the mobile device, where it is received and buffered before being streamed to the cloud for storage.
- the received data is processed by BodySleep2.0, and the analysis output provided to an adequate person responsible for monitoring the patient sleep performance or treatment compliance.
- the device is a recorder (for example, such as a Nox T3s recorder), that stores the data, the data is then uploaded during or after the study to the cloud OR the data on the device is downloaded upon its physical return to the clinic/operation where BodySleep2.0 is used for analyzing like in Method 1. The patient does not need to download an app.
- Calibrating a simple sleep study device [0350] According to a calibrating method: A patient uses a consumer grade or a simple medical device to monitor his treatment effectiveness. A RIP belt sensor (preferably a 2-belt sensor and for single patient use), is sent to a customer on request.
- the patient downloads an app in his mobile phone that is paired with the sensor for wireless communications (such as BLE).
- the patient sleeps with the sensor that streams the recorded data either directly or buffered to the mobile device, where it is received and buffered before being streamed to the cloud for storage.
- the received data is processed by a BodySleep processor, for example, the Nox BodySleep2.0, and the analysis output is used to calibrate the consumer grade or simple medical device as described in US Application No.17/351,933.
- a BodySleep method is performed using a BodySleep sensor, such as a Nox BodySleep2.0 Sensor, which records a patient using CPAP, preferable over multiple nights.
- a BodySleep analysis is performed, for example, according to the BodySleep2.0 sleep analysis.
- a comparison between the received data from the CPAP and the measured data from BodySleep2.0 is used to augment the accuracy of the CPAP data as described in WN Ref. No US Application No.17/351,933.
- a post-data analysis is performed on stored CPAP data to determine how the patient has been trending.
- the calibrated CPAP data model may be used in the future to keep trending the patient with high accuracy and to identify when he is at risk of quitting therapy.
- Using one or more RIP belts for example, two RIP belts to diagnose sleep apnea.
- sleep apnea is a disease where a patient periodically stops breathing (apnea) or has severely reduced airflow which terminates in a drop in the blood oxygen saturation or an arousal (hypopnea). Apneas and hypopneas occur during sleep.
- Today sleep apnea is diagnosed by measuring breathing, and blood oxygen saturation.
- electroencephalography (EEG), electrooculography (EOG), and electromyography (EMG) are also used.
- the reduction in airflow is typically measured by a nasal cannula, the desaturation is measured by an oximeter, the arousals are detected in the EEG signals, and various sleep stages are detected using the EEG, EOG, and EMG signals.
- AASM American Academy of Sleep Medicine
- hypopneas and apneas are defined as certain reduction in breathing followed by a drop in blood oxygen saturation or an arousal. Even though a drop in blood oxygen saturation is often used to score hypopneas, it has been shown that most respiratory events terminate in arousals.
- the systems, sensors, and methods described herein is a foundation that can be used to design and build a new and novel device to diagnose sleep apnea and monitor sleep apnea treatment.
- the device is a small electronic device using two RIP belts, one placed around the thorax to measure thoracic breathing motions, and another one placed around the abdomen to measure abdomen breathing movements.
- the device is easy to use by the patient, can be easily shipped in the mail, is inexpensive so it is not costly if devices get lost or delayed, the devices can be disposable, the devices can live with the patient, and the devices can be used once or multiple times by the patient.
- a method is provided based on the systems, sensors, and methods described herein (e.g., as implemented in a Nox BodySleep2.0) for diagnosing sleep apnea.
- the method comprises sending at least a 2-belt RIP sensor (which may be single patient use belts) to a customer on request.
- the patient downloads an app in his mobile phone that is paired with the sensor for wireless communications (such as BLE).
- the patient sleeps with the sensor that streams the recorded data either directly or buffered to the mobile device, where it is received and buffered before being streamed to the cloud for storage.
- the received data is processed by a system configured to perform the BodySleep analysis described herein (for example, the Nox BodySleep2.0), and the analysis output provided to an adequate person responsible for providing the patient with the correct diagnosis of sleep apnea.
- a system configured to perform the BodySleep analysis described herein (for example, the Nox BodySleep2.0), and the analysis output provided to an adequate person responsible for providing the patient with the correct diagnosis of sleep apnea.
- a second is also provided, similar to the method above, except the device is a recorder (like a Nox T3 device), that stores the data, the data is then uploaded during or after the study to the cloud or the data on the device is downloaded upon its physical return to the clinic/operation where BodySleep2.0 is used for analyzing like in Method 1. The patient does not need to download an app.
- PLMS Periodic Limb Movements of Sleep
- PSG polysomnography
- EEG electroencephalography
- EEG electromyography
- the EMG signals are recorded on the limbs to detect characteristic increases in muscle tone associated with the muscle twitching.
- the EEG signals are recorded to detect arousals associated with muscle twitching.
- the PLMS events have characteristic periodicity that are reflected in the EMG and arousal events.
- arousals associated with the PLMS events are not associated with other causes of arousals that may be periodic such as breathing cessation during sleep (i.e. apneas and hypopneas).
- apneas and hypopneas causes of arousals that may be periodic
- Conventionally PLMS is measured in PSG using EMG electrodes on the right and left leg and when the muscle is active, it shows up in the EMG.
- PLMS Periodic Limb Movement during Sleep
- the muscular activity is periodic and must fulfill a certain criterion to be distinguishable from movements caused by arousals from sleep apnea.
- the period of PLMS is 20-30 seconds but can be longer, and that overlaps with the frequency of severe OSA.
- PLMS does not always cause cortex arousal as defined in the sleep scoring manual, but if it doesn't affect the sleep pattern it is not a problem. While the interscorer reliability of EEG manually scored arousals is low (60%) we assume that the auto scored BodySleep2.0 arousals are both sensitive and specific to real events taking place in the body. And if only PLMS activities that cause arousals matter, the PLMS can be confirmed by the following method. [0365] Some attempts have been made to score PLMS from body signals, especially Pleth from oximetry or PAT devices.
- a device that contains at least one and preferably at least two RIP belts where an analysis such as the Nox BodySleep2.0 is used to determine periods of wake, REM sleep, and non-REM sleep, and detect arousal events it is possible to detect arousals during different stages of sleep.
- the two RIP belts can be used to detect apneas and hypopneas since the RIP belts measure the breathing movements of a patient.
- the breathing movements can be used to construct a signal that is proportional to flow during breathing.
- the RIP flow signal can be used to detect apneas and hypopneas.
- arousals that are not associated with respiratory events, occur during sleep, and are periodic. These arousals can be determined to be associated with PLMS and are the foundation of using the RIP belts and the BodySleep analysis method to diagnose PLMS, instead of requiring a full PSG sleep study.
- the sensitivity of the systems, sensors, and methods described herein is preferably trained to match the PSG scoring of arousals as well as possible.
- the arousal model may be used and then the periodicity may be used to determine if the events detected originated from PLMS or something else.
- the detection of arousal and arousal-associated events can be used to capture "switching between autonomic and somatic respiratory control" without requiring a capturing of the respiratory recovery breath response in case of sleep apnea.
- the model may be used For PLMS analysis as the arousal model is not only capturing the recovery-breath characteristics associated with sleep apneas but as well the change of respiratory control between the autonomic and somatic systems when the patient is aroused.
- the periodicity may be used to determine if the events detected originated from PLMS or something else.
- a method is provided for diagnosing PLMS. At least a 2 RIP belt sensor (preferably single patient use), is sent to a customer on request. The patient downloads an app in his mobile phone that is paired with the sensor for wireless communications (such as BLE). The patient sleeps with the sensor that streams the recorded data either directly or buffered to the mobile device, where it is received and buffered before being streamed to the cloud for storage.
- the received data is processed the systems, sensors, and/or methods described herein (e.g., as implemented in a Nox BodySleep2.0 system).
- Arousals and respiratory events are detected.
- Arousals associated with apneas or hypopneas are excluded and the periodicity of the remaining arousals is analyzed. It is determined if a series of arousals are periodic, repeating within a regular period (allowing certain variance) as is used for scoring PLMS EEG signals in PSG.
- a PLMS period is marked over the time where PLMS is repeating and mark the periodic arousal events within that period as LM.
- the analysis output is provided to an adequate person responsible for providing the patient with the correct diagnosis of PLMS.
- a second PLMS diagnosing method is also provided, which is same as above- described method except the device is a recorder (like a Nox T3s), that stores the data. The data is then uploaded during or after the study to the cloud or the data on the device is downloaded upon its physical return to the clinic/operation where the systems, sensors, and methods described herein (e.g., as implemented in a Nox BodySleep2.0 system) are used for analyzing like in the above method. The patient does not need to download an app.
- a third PLMS method is provided, similar to the first PLMS method above, except arousals and sleep stages are determined using EEG/EOG/chin EMG as per a standard PSG sleep recording.
- the arousals and sleep stages are used as described in the first PLMS method above when they were derived using the analysis provided by the systems, sensors, and methods described herein (e.g., as implemented in a Nox BodySleep2.0 system).
- Introduction: Diagnosis of Narcolepsy [0372] Patients suffering from Narcolepsy are known to have cataplexy, where they lose muscle tone in the body. They are also known to transition from wake to rapid-eye movement (REM) sleep, which is a characteristic of the disease.
- REM rapid-eye movement
- REM sleep is characterized with the paralysis of the skeletal muscles, including but not limited to the intercostal muscles of the thorax.
- Today Narcolepsy is diagnosed in several ways.
- One method of diagnosing Narcolepsy is to use a special sleep study protocol called Multiple Sleep Latency Test (MSLT) or a Maintenance of Wakefulness Test (MWT).
- MSLT Multiple Sleep Latency Test
- MMWT Maintenance of Wakefulness Test
- Both the MSLT and MWT sleep tests require a patient to spend a night at a hospital where an in-lab polysomnography (PSG) sleep study is performed on them. The following day the patient continues to wear the PSG sleep recording device and follows a strict protocol while being monitored by a sleep technician or a nurse. These sleep studies are uncomfortable for the patient and require extensive hospital resources.
- PSG polysomnography
- the systems, sensors, and methods described herein is a sleep stage and arousal detection AI analysis which uses the breathing movements of the thorax and abdomen to estimate Wake, REM, and Non-REM sleep periods.
- REM sleep and during cataplexy the skeletal muscles are paralyzed while the diaphragm is active. This has a significant impact on how the breathing movements of the thorax and abdomen look like.
- RIP respiratory inductance plethysmography
- FIG.20 shows an example of how the thoracic RIP signal changes in a period of REM sleep interrupted by an awakening and a period of non-REM sleep.
- the colored markers indicate 30 second periods that have been scored as a certain sleep stage by a trained sleep technician using electroencephalogram (EEG), electrooculogram (EOG), and electromyogram (EMG) signals.
- EEG electroencephalogram
- EEG electrooculogram
- EMG electromyogram
- the scoring of sleep stages by a sleep technician using the EEG/EOG/EMG signals is the state-of-the-art approach to score sleep. These sleep stages are presented as a reference to highlight how the abdomen and thorax RIP signals behave during REM, Wake, and Non-REM.
- FIG.20 shows that the amplitude of the thoracic RIP signal is lower during the REM periods than during the Wake and non-REM periods. Furthermore, the amplitude of the thoracic signal is variable. This is indicative of intercostal muscle paralyzation.
- a combination of sleep staging using the EEG/EOG/EMG and the analysis of the systems, sensors, and methods described herein may be useful to detect periods of REM sleep or periods where there are discrepancies between the state-of-the-art EEG/EOG/EMG sleep staging and the sleep staging of the BodySleep analysis.
- narcolepsy is characterized by sleep periods where sleep technicians struggle to identify the sleep stages from the EEG/EOG/EMG signals and the patient may describe periods of where they are aware but still cannot move or control their thoughts.
- a method of diagnosing Narcolepsy is provided, including using the systems, sensors, and methods described herein (e.g., as implemented in a Nox BodySleep2.0 system) to detect the transitions from wake to REM which could be used to provide input in the diagnosis of Narcolepsy.
- the BodySleep analysis can be used to detect cataplexy or loss of muscle tone in the body.
- Dementia detection is an umbrella term used for general decline in cognitive abilities that impacts a person’s ability to perform everyday activities. Dementia includes causes such as Alzheimer’s disease, Lewy Body Dementia, Parkinson’s Disease, and other causes. Dementia has been shown to correlate with sleep disorders and sleep disorders may even accelerate the onset of Dementia.Specific sleep disorders are known to have predictive power when detecting or diagnosing certain types of dementia.
- REM sleep behavior disorder is a core feature in the diagnosis of Lewy Body Dementia.
- RBD is characterized by the patient losing muscle paralysis (atonia) during REM sleep.
- RBD may appear years or decades before other symptoms of Lewy Body Dementia.
- a sleep recording device consisting of one or more RIP belts, preferably at least two RIP belts, using the systems, sensors, and methods described herein (e.g., as implemented in a Nox BodySleep2.0 system) may be used to diagnose RBD.
- the BodySleep methods described can distinguish between wake and sleep and can distinguish between REM and non-REM sleep.
- a method of detecting dementia is provided.
- RBD is detected by identifying periods of REM sleep where the patient does not have atonia.
- PLMS is detected using the methods described in the section Diagnosing PLMS.
- any of the parameters mentioned in the Meta analysis including total sleep time, sleep efficiency, REM sleep percentage, increase in wake after sleep onset, REM latency, apnea hypopnea index, and PLMS.
- HSAT augmentation A system, sensor, and methods described herein (e.g., as implemented in a Nox BodySleep2.0 system) is a massive improvement for HSAT studies as it allows the correct detection of all the AHI events, hypopneas that do not end in desaturations but only arousals, and provides a classification of sleep stages into WAKE/NREM/REM. Even if this provides a conclusive sleep apnea study regardless of the AHI index we do not have a reliable way of providing the same accuracy of sleep profiles as received from an in-lab PSG.
- NREM N1, N2 and N3
- SAS SelfAppliedSomnography
- HSAT+ has been used to score arousals and sleep stages before.
- a method is provide for augmenting HSAT with the systems, sensors, and methods described herein (e.g., as implemented in a Nox BodySleep2.0 system).
- a recording device such as a Nox T3s device is used to record a HSAT study with one or two additional frontal-EEG channels and one or more RIP belts, preferably at least 2 RIP belts.
- a BodySleep system, sensors, or method as described herein is used to derive all the parameters that can be derived from the BodySleep signals.
- An auto scoring is run on the EEG signals, determining sleep stages and arousals.
- the acceleration sensors are however both relatively expensive with the total cost of the device and consume power that enlarges the battery needed for the same recording time. It would therefore be beneficial if the sensor could be removed but the position and activity information could be derived in a different way.
- the RIP belts are indeed a movement sensor that is affected by any body motion that affects the form of the abdomen or the thorax. Additionally, the alignment of the organs changes with the different body positions, and this affects the movements of the thorax towards the abdomen. Upright position means that the abdomen pressure is taken off the diaphragm and therefore the thorax compartment and this shows up in the RIP signals.
- Supine means that the rib-cage is free from the arms to move up and down, while left and right positions are hindered by the pressure on the side, especially if an arm is pressing the side. Prone position presses on both compartments.
- Table 4-1 the validation and performance of a system and method as described above are provided wherein a 2-belt RIP system was used to determine the body position of the subject, comparing the predicted label of the body position to the true label of the body position, with an accuracy of 0.82 for the non-supine body position, 0.98 for the upright body position, and 0.82 for the supine body position.
- a method for augmenting a HSAT study includes recording with a recording device, such as a Nox T3s, a HSAT study with one or two additional frontal- EEG channels.
- a BodySleep analysis method or system, as described herein, is used to derive all the parameters that can be derived from the BS signals.
- An auto scoring is run on the EEG signals, determining sleep stages and arousals.
- the results are combined from both in a relative manner for highest accuracy PSG like outcomes, including PLMS from methode #1 above, sleep staging, sleep time, and combined/optimal arousals.
- HSAT+ has been used to score arousals and sleep stages before.
- both providing accurate timing of the NREM periods and all the arousals, to both get the most accurate classification of sleep during NREM and improve the accuracy of the overall sleep staging and arousals, is something new.
- a sleep care management method is provided wherein one or more RIP belts, preferably two RIP belts and preferably single patient use belts, are provide to a customer on request. An app is provided to the patient to download. The patient downloads an app in his mobile phone that is paired with the sensor for wireless communications (such as BLE).
- the received data is processed by the systems, sensors, and methods described herein (e.g., as implemented in a Nox BodySleep2.0) and the analysis output provided to an adequate person responsible for monitoring the patient sleep performance or treatment compliance.
- a second method is provided similar to the above sleep care management method above, except the device is a recorder (like the Nox T3s), that stores the data, the data is then during or after the study uploaded to the cloud OR the data on the device is downloaded on its physical return to the clinic/operation where BodySleep analysis method or system is used for analysing like in the above method.
- the CPAP is however only in an indirect connection to the patient, "sees" the patient through the air-tube between the CPAP and the patient, based on the air-pressure and air-flow signals. Even if this gives the PAP device significant information on how well the patient is breathing, it does not have much to work with regarding how well he sleeps. This is especially difficult, as a patient on an inefficient treatment might not have direct apneas, but is half-cured, meaning that he might be struggling and having arousals. Similar to the ideas described in US Application No.
- a method is provided wherein a BodySleep sensor performs a recording on a patient using CPAP, preferable over multiple nights, a BodySleep analysis method is performed. The comparison is used between the received data from the CPAP and the measured data from BodySleep analysis method to augment the accuracy of the CPAP data. Post-data analysis is performed on stored CPAP data to determine how the patient has been trending. The calibrated CPAP data model may be used in the future to keep trending the patient with high accuracy and to identify when he is at risk of quitting therapy.
- This disclosure provides various examples, embodiments, systems, devices, and methods that predict sleep arousals using non-EEG signal groups. Methods and systems are disclosed herein that predict sleep arousals without requiring EEG signal groups. Also provided, as embodiments, are methods and systems using on an effective AI model tailored for HSAT, that can predict or identify sleep arousals using non-brain signal groups, or in other words using signals not obtained from a brain-machine-interface (BMI). Also provided, as embodiments, are methods and systems using on an effective AI model tailored for HSAT, that can predict sleep arousals using only non-EEG signal groups.
- BMI brain-machine-interface
- Methods, Devices, and Systems for for determining an arousal in a sleep study of a subject using one or more body signals [0408] 1. A method for determining an arousal or arousal-associated event in a sleep study of a subject, the method comprising: obtaining data from one or more body signals, the one or more body signals being non-brain signals; and determining an arousal or arousal-associated event of the subject using the data from one or more body signals. [0409] 2.
- determining the arousal or arousal-associated event includes using classifier to perform a classification of the of the one or more body signals, wherein the classifier is a neural network, artificial neural network, decision tree or trees, forests of decision trees, clustering, and/or a support vector machine.
- the classifier is a neural network, artificial neural network, decision tree or trees, forests of decision trees, clustering, and/or a support vector machine.
- the classifier is a convolutional neural network (CNN).
- CNN convolutional neural network
- obtaining the one or more body signals include obtaining a thorax effort signal (T), the thorax effort signal (T) being an indicator of a thoracic component of the respiratory effort.
- obtaining the one or more body signals include respiratory inductance plethysmography (RIP) signals and wherein obtaining the one or more body signals include obtaining an abdomen effort signal (A), the abdomen effort signal (A) being an indicator of an abdominal component of the respiratory effort.
- RIP respiratory inductance plethysmography
- obtaining the one or more body signals includes obtaining a signal of an acceleration signal indicating an acceleration of a body part of the subject.
- 11. The method according to any one or a combination of one or more of 1–10 above and/or 12–44 below, wherein obtaining the one or more body signals includes obtaining a cardiac signal of the subject.
- 12. The method according to any one or a combination of one or more of 1–11 above and/or 13–44 below, wherein the one or more body signals are obtained from the subject by non-invasive means. [0420] 13.
- the first respiratory component signal includes an abdomen respiratory volume signal, a thorax respiratory volume signal, the sum of the abdomen and thorax respiratory volume signals (RIPSum), a time derivative of the abdomen respiratory volume signal, a time derivative of the thorax respiratory volume signal, a time derivative of the sum of the abdomen respiratory volume signal and the thorax respiratory volume signal (RIPflow), a respiratory phase signal indicating the phase difference between the abdomen respiratory volume signal and the thorax respiratory volume signal, or a respiratory rate signal (RespRate).
- the first respiratory component signal includes an abdomen respiratory volume signal, a thorax respiratory volume signal, the sum of the abdomen and thorax respiratory volume signals (RIPSum), a time derivative of the abdomen respiratory volume signal, a time derivative of the thorax respiratory volume signal, a time derivative of the sum of the abdomen respiratory volume signal and the thorax respiratory volume signal (RIPflow), a respiratory phase signal indicating the phase difference between the abdomen respiratory volume signal and the thorax respiratory volume signal, or a respiratory rate
- a method of estimating an apnea-hypopnea-index (AHI) comprising the method for determining an arousal or arousal-associated event in a sleep study of the subject according to any one or a combination of one or more of 1–18 above or 20–44 below.
- a method for determining an arousal or arousal-associated event in a sleep study of a subject comprising: obtaining data from one or more body signals, the one or more body signals being non-brain signals, the one or more body signals including an oximetry signal; and determining an arousal of the subject using the data from one or more body signals. [0434] 27.
- determining the arousal or arousal-associated event includes using classifier to perform a classification of the of the one or more body signals, wherein the classifier is a neural network, artificial neural network, decision tree or trees, forests of decision trees, clustering, and/or a support vector machine.
- the classifier is a convolutional neural network (CNN).
- a method of estimating an apnea-hypopnea-index (AHI) of a subject in a sleep study comprising: obtaining data from one or more body signals, the one or more body signals being non-brain signals; and determining an apnea-hypopnea-index (AHI) of the subject using the data from one or more body signals.
- AHI apnea-hypopnea-index
- determining the arousal or arousal-associated event includes using classifier to perform a classification of the of the one or more body signals, wherein the classifier is a neural network, artificial neural network, decision tree or trees, forests of decision trees, clustering, and/or a support vector machine.
- the classifier is a convolutional neural network (CNN).
- a method for determining an apnea in a sleep study of a subject comprising: obtaining data from one or more body signals, the one or more body signals being non-brain signals, and one of the body signals being an abdomen RIP signal and/or a thoracic RIP signal; and determining an apnea of the subject using the data from one or more body signals.
- a method for determining a hypopnea in a sleep study of a subject comprising: obtaining data from one or more body signals, the one or more body signals being non-brain signals; and one of the body signals being an abdomen RIP signal and/or a thoracic RIP signal; and determining an hypopnea of the subject using the data from one or more body signals.
- a method for determining a RERA in a sleep study of a subject comprising: obtaining data from one or more body signals, the one or more body signals being non-brain signals, one of the body signals being an abdomen RIP signal and/or a thoracic RIP signal; and determining a RERA of the subject using the data from one or more body signals.
- a system for determining an arousal or arousal-associated event of a subject comprising: a receiver configured to receive one or more body signals, the one or more body signals being non-brain signals; a memory storage having instructions stored thereon; and the processor configured execute the instructions stored on the memory storage and thereby perform the method according to any one of methods 1–45 above.
- a receiver configured to receive one or more body signals, the one or more body signals being non-brain signals
- a memory storage having instructions stored thereon
- the processor configured execute the instructions stored on the memory storage and thereby perform the method according to any one of methods 1–45 above.
- system is configured to obtain the data from the one or more body signals by receiving a transmission, either wireless or by hardwire, of said data.
- a hardware storage device having stored thereon computer executable instructions which, when executed by one or more processors of a computer system, configure the computer system to perform at least the following: obtain data from one or more body signals, the one or more body signals being non-brain signals; determine an arousal or arousal-associated event of the subject using the data from one or more body signals.
- an AHI is derived from RIP signals or one or more RIP belts
- the method further comprises: determining arousals and/or arousal-associated events of the subject using the data from the RIP signals; detecting apneas (e.g., based on 90% drop in flow) and potential hypopneas (for example, based on >30% drop); associating the potential hypopneas that have >3%/4% drop in SpO2; associating the potential Hypopneas that are associated with an arousal; deriving the total sleep time; and then based thereon, calculating the AHI for the sleep study in a manner similar to the conventional way an AHI would be calculated as if the sleep study included an EEG signal.
- AHI Apnea Hypopnea Index
- AASM The American Academy of Sleep Medicine; ADHD Attention deficit hyperactivity disorder; AF Atrial fibrillation; AHI Apnea-Hypopnea index; AI Artificial intelligence; ANN Artificial neural network; ATX Atomoxetine; BDZ Benzodiazepans; BMI Body mass index; BPAP Bi- level positive airway pressure; CAD Coronary artery disease; CNN Convolutional Neural Networks; COPD Chronic obstructive pulmonary disease; CPAP Continuous positive airway pressure; CSA Central sleep apnea; DMD Duchenne muscular dystrophy; EEG Electroencephalogram; EEO Electro-oculogram; HGNS Hypoglossal nerve stimulation; HSAT Home sleep apnea test; HSAT+ Enriched home sleep ap
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Health & Medical Sciences (AREA)
- Veterinary Medicine (AREA)
- Pathology (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Medical Informatics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- Biophysics (AREA)
- Public Health (AREA)
- Physiology (AREA)
- Artificial Intelligence (AREA)
- Psychiatry (AREA)
- Pulmonology (AREA)
- Evolutionary Computation (AREA)
- Fuzzy Systems (AREA)
- Mathematical Physics (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Signal Processing (AREA)
- Dentistry (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Anesthesiology (AREA)
- Psychology (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
Description
Claims
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US202363490984P | 2023-03-17 | 2023-03-17 | |
| US63/490,984 | 2023-03-17 | ||
| US202363613562P | 2023-12-21 | 2023-12-21 | |
| US63/613,562 | 2023-12-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2024194789A1 true WO2024194789A1 (en) | 2024-09-26 |
Family
ID=90468480
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IB2024/052615 Pending WO2024194789A1 (en) | 2023-03-17 | 2024-03-18 | System and method for determining arousals and arousal-associated events of a sleep study using non-brain body signals or without requiring brain signals |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US20240306983A1 (en) |
| WO (1) | WO2024194789A1 (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1938862A2 (en) * | 2003-08-18 | 2008-07-02 | Cardiac Pacemakers, Inc. | Disordered breathing management system and methods |
| US20150126879A1 (en) | 2013-11-06 | 2015-05-07 | Nox Medical | Method, apparatus, and system for measuring respiratory effort |
| US20180049678A1 (en) | 2016-08-19 | 2018-02-22 | Nox Medical | Method, apparatus, and system for measuring respiratory effort of a subject |
| US20180116588A1 (en) * | 2015-05-13 | 2018-05-03 | Resmed Limited | Systems and methods for screening, diagnosis and monitoring sleep-disordered breathing |
| US20190274586A1 (en) | 2017-09-08 | 2019-09-12 | Nox Medical Ehf | System and method for non-invasively determining an internal component of respiratory effort |
| US20210085242A1 (en) | 2019-09-20 | 2021-03-25 | Nox Medical Ehf | System and method for determining sleep stages based on non-cardiac body signals |
| EP3875026A1 (en) * | 2020-03-03 | 2021-09-08 | Koninklijke Philips N.V. | Sleep apnea detection system and method |
| US20210393211A1 (en) | 2020-06-18 | 2021-12-23 | Nox Medical Ehf | Personalized sleep classifying methods and systems |
-
2024
- 2024-03-18 WO PCT/IB2024/052615 patent/WO2024194789A1/en active Pending
- 2024-03-18 US US18/608,526 patent/US20240306983A1/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1938862A2 (en) * | 2003-08-18 | 2008-07-02 | Cardiac Pacemakers, Inc. | Disordered breathing management system and methods |
| US20150126879A1 (en) | 2013-11-06 | 2015-05-07 | Nox Medical | Method, apparatus, and system for measuring respiratory effort |
| US20180116588A1 (en) * | 2015-05-13 | 2018-05-03 | Resmed Limited | Systems and methods for screening, diagnosis and monitoring sleep-disordered breathing |
| US20180049678A1 (en) | 2016-08-19 | 2018-02-22 | Nox Medical | Method, apparatus, and system for measuring respiratory effort of a subject |
| US20190274586A1 (en) | 2017-09-08 | 2019-09-12 | Nox Medical Ehf | System and method for non-invasively determining an internal component of respiratory effort |
| US20210085242A1 (en) | 2019-09-20 | 2021-03-25 | Nox Medical Ehf | System and method for determining sleep stages based on non-cardiac body signals |
| EP3875026A1 (en) * | 2020-03-03 | 2021-09-08 | Koninklijke Philips N.V. | Sleep apnea detection system and method |
| US20210393211A1 (en) | 2020-06-18 | 2021-12-23 | Nox Medical Ehf | Personalized sleep classifying methods and systems |
Non-Patent Citations (5)
Also Published As
| Publication number | Publication date |
|---|---|
| US20240306983A1 (en) | 2024-09-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Roebuck et al. | A review of signals used in sleep analysis | |
| Mendonça et al. | A review of approaches for sleep quality analysis | |
| Van de Water et al. | Objective measurements of sleep for non‐laboratory settings as alternatives to polysomnography–a systematic review | |
| Lechat et al. | New and emerging approaches to better define sleep disruption and its consequences | |
| US20210085242A1 (en) | System and method for determining sleep stages based on non-cardiac body signals | |
| Bertoni et al. | Towards patient-centered diagnosis of pediatric obstructive sleep apnea—a review of biomedical engineering strategies | |
| US20220218273A1 (en) | System and Method for Noninvasive Sleep Monitoring and Reporting | |
| Vitazkova et al. | Transforming sleep monitoring: review of wearable and remote devices advancing home polysomnography and their role in predicting neurological disorders | |
| Bradley et al. | Pulse transit time and assessment of childhood sleep disordered breathing | |
| US20170332917A1 (en) | Non-intrusive portable sleep apnea assessment system | |
| Akhter et al. | Detection of REM/NREM snores in obstructive sleep apnoea patients using a machine learning technique | |
| US20240306983A1 (en) | System and method for determining arousals and arousal-associated events of a sleep study using non-brain body signals or without requiring brain signals | |
| US20250025098A1 (en) | Systems, devices, and method for determining and monitoring sleep disorders based on determined arousals and arousal-associated events using non-brain body signals or without requiring brain signals | |
| Jirakittayakorn et al. | RespNet: A Dual-Network Approach for Automated OSA Severity Classification Utilizing PSG Type III Signals | |
| US20250325223A1 (en) | Computer-implemented method, and emg device to measure electric a muscle | |
| Finnsson et al. | Detecting arousals and sleep from respiratory inductance plethysmography | |
| US12257069B2 (en) | System comprising a sensing unit and a device for processing data relating to disturbances that may occur during the sleep of a subject | |
| Roomkham | The potential of personal devices in large-scale sleep studies | |
| Verbraecken | Sleep Studies | |
| Vitulano | Nocturnal Monitoring in the Evaluation of Continuous Positive Airway Pressure | |
| Fonseca | Home sleep monitoring | |
| Penzel | Technology to Assess Sleep, An Issue of Sleep Medicine Clinics | |
| Ryser | Movement-based sleep detection–a wearable sensor system to assess quantity and quality of sleep | |
| Piccin | Monitoring Positive Pressure Therapy in Sleep-Related Breathing Disorders | |
| da Silva Marçal | A Single Channel High-Resolution Snoring Signal as a Medical Tool for Obstructive Sleep Apnoea Assessment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 24714029 Country of ref document: EP Kind code of ref document: A1 |
|
| WWE | Wipo information: entry into national phase |
Ref document number: 2024714029 Country of ref document: EP |
|
| NENP | Non-entry into the national phase |
Ref country code: DE |
|
| ENP | Entry into the national phase |
Ref document number: 2024714029 Country of ref document: EP Effective date: 20251017 |
|
| ENP | Entry into the national phase |
Ref document number: 2024714029 Country of ref document: EP Effective date: 20251017 |
|
| ENP | Entry into the national phase |
Ref document number: 2024714029 Country of ref document: EP Effective date: 20251017 |
|
| ENP | Entry into the national phase |
Ref document number: 2024714029 Country of ref document: EP Effective date: 20251017 |
|
| ENP | Entry into the national phase |
Ref document number: 2024714029 Country of ref document: EP Effective date: 20251017 |